Installing chain tensioners from SE racing on a Big Ripper

Рет қаралды 49,068

3 жыл бұрын

Why are chain tensioners important? Glad you asked. They keep your back wheel lined up and keep you rolling smoothly down the road. I'll show you how I like to install and adjust them and make sure everything is good to go.

Пікірлер: 188

@atitagain83 4 ай бұрын

Came for the BMX, stayed for the Pit Vipers.

@susanmary6864 3 жыл бұрын

he actually described everything he was doing. like the wrench sizes, allen wrench sizes. it makes it a lot easier then guessing the sizes

@taylorwhite5149 2 жыл бұрын

Love that you answered 90 people each asking thw same question about about pegs. I always scroll comments before I ask anything, I must be one of the only ones 😄

@BigBikeBMX 2 жыл бұрын

Taylor, you're my favorite person in the world for this. I also just answered this question another three times tonight :)

@haferman1 Жыл бұрын

I'm scrolling to find the answer...

@XGaming1 3 жыл бұрын

I didn’t even know these things existed till today, I always have trouble lining up and tightening my back wheel and having the chain right at the same time so thank you for this video. Definitely going to try these.

@BigBikeBMX 3 жыл бұрын

They’re a game-changer. Pull the wheel tight and finger-tighten the bolts and then fine tune with the tensioners🤘

@dlux626 5 ай бұрын

Proper maintenance make riding more fun!

@raymondchew8894 3 жыл бұрын

Thanks for explaining how to install and set up the chain tensioner. It will helpful for me who trying to solve chain skipping for a used bike I just bought for my grandson.

@seanacevedo3772 3 жыл бұрын

Appreciate the vid bro got my tensioners coming in today excited to put them on, stay safe bro your chill af

@TheDRUMSMYWIFE 3 жыл бұрын

I always have a not so snug chain after so many rides and the wheel alignment is always out of wack for me. But after watching this video it helps me out when I do get some Chain Tensioners. I’m gonna go with some black ops CT’s to go with some black ops parts that are already on my So Cal. Thanks for the informative video. Looks like a “set it and forget it” kinda piece of doohickey

@wozgetley5722 3 жыл бұрын

Cool vid never used them before 🤘🤘 keep em coming 👌🤘🤘

@krashbandicoot78 3 жыл бұрын

Thanks for the great video learned alot. Gonna order a pair now!!!

@rickmonster636 3 жыл бұрын

Always informative and entertaining. Thanks for posting such good Content

@BigBikeBMX 3 жыл бұрын

Thanks Rick🤘

@techjunkie68smusicandtech56 Жыл бұрын

Looks nice, I am wanting some of those for my So Cal Flyer soon. I have the stealth black So Cal Flyer with gold parts, looks and rides great!

@trapgonzalez3449 3 жыл бұрын

Thank you so much Isaac new to bmx’s never got super in depth with them as a kid now here I am at 30 trying to figure out how things work appreciate the videos and tutorials brother !

@BigBikeBMX 3 жыл бұрын

Thanks for watching bro! I'm learning as I go here too. Lots of new tech in BMX these days! Welcome to the Big Bike BMX family!

@trapgonzalez3449 3 жыл бұрын

@@BigBikeBMX appreciate you brother awesome content it was hard not to watch and subscribe keep up the great work blessings to you and the family

@ofrenic 3 жыл бұрын

I'm only getting into bmx now and I'm 27, bit late to the party but we're here nonetheless

@erikjensen6503 Жыл бұрын

Thanks for sharing until i watched your freewheel replacement i had no idea they even made them for bikes. Just got my son the SE Big Ripper HD for his birthday and now I'm going to find those gold chain adjusters! They look just like what are on my motorcycles but smaller. Thanks for your videos and time!

@BigBikeBMX Жыл бұрын

Your local SE Dealer can get the gold tensioners pretty quick. They’ll look great with the gold pads🤘🤘

@gilbertvalenciano2931 3 жыл бұрын

Hi from Safford Arizona love your videos

@BigBikeBMX 3 жыл бұрын

Gilbert Valenciano hey man! Thanks for watching!

@paulgreenwell8949 2 жыл бұрын

Nice video bro much respect got some for my racing bike bmx rides smoothly

@dominicsoto2162 3 жыл бұрын

Would be much appreciated if you did a vid on adjusting brakes. I personally haven’t had an issue with my brakes yet. But it’s only a matter of time. Another great vid!

@BigBikeBMX 3 жыл бұрын

Will do! Thanks for the comment and for watching bro!

@marioavila1235 3 жыл бұрын

Thanks 4 posting, I wish youtube would let me reply with a photo in my comments.....2 show U my bad ass cruiser.....Anyway I got caught cruising when my long chain cruiser, when the rear tire moved forward & I was nowhere near access 2 any tools. So I was walking my Custom Cruiser which always draws attention ...and peeps were like "Nice bike" ....while I was embarrassed cuz in my mind they were like " too bad it doesn't even work " ...lol That will never happen again...cuz I did the research & found out about this device that I will now install after this video .... Thanks

@BigBikeBMX 3 жыл бұрын

They’re perfect for that exact situation 🤘

@XGaming1 3 жыл бұрын

Cool glasses man

@larsyoung 3 жыл бұрын

Super informative video!!! I’m definitely goin got put them on any of my SE Bikes that do have them. Thanks!!! Oh yeah...DOPE GLASSES!!!!! Super Fly! 🙏🏾😎🏁

@BigBikeBMX 3 жыл бұрын

Thanks man! They’re definitely useful and handy for keeping things lined up🤘

@Dogmeat_donnie 2 жыл бұрын

@@BigBikeBMX oh that's why the funny [popping type sounds sometimes happen when I tighten my chain!!! It's too tight. Just got my tensioners today so now I'll know, thanks for the helpful video.

@BigBikeBMX 2 жыл бұрын

@@Dogmeat_donnie thanks Paul! That angry chain noise was annoying. Simple fix too👍

@Mctzuma 3 жыл бұрын

Thanks for the help now I know what there used for

@rexvapes9589 3 жыл бұрын

Thanks for video, just ordered some for my Flyer

@xdzc1 2 жыл бұрын

what size tensioner did u get for a flyer

@mikeodell5915 2 жыл бұрын

Great video and nice bike (as well as the H1)

@BigBikeBMX 2 жыл бұрын

Thanks Mike! That H1 sucks. My minivan is more reliable lol

@Short_Kid2007 3 жыл бұрын

Thank you so much it fixed my box bike

@miketaylor5141 Ай бұрын

Beautiful bike! Rad color scheme

@john_wisdom 3 жыл бұрын

Cool video, informative, no bs. Nice.

@hiphopsecops 3 жыл бұрын

Man those glasses are dope! Thanks for the video!

@BigBikeBMX 3 жыл бұрын

It was so bright in Phoenix today. Had to wear them

@loder6179 3 жыл бұрын

i never knew a chain could be "too tight" thanks for the advice

@BigBikeBMX 3 жыл бұрын

They snap if they’re too tight. Chain tensioners let you dial in the wheel alignment and get things perfect

@vice6996 Жыл бұрын

me neither hahaha. i'm sure i wasn't the only kid in their garage with the rear tire loosened up and pulling it back with all my strength while trying to tighten the axle nuts back down and trying to keep the tire aligned. just barely a slight wobble, good nuff. send it!

@Cisco0615 5 ай бұрын

Great informative video, thanks

@BigBikeBMX 5 ай бұрын

Glad you enjoyed it! Thanks for watching

@youngjimjones 3 жыл бұрын

Diggin the Macho Man Randy Savage Sunglasses! Awesome vid too

@BigBikeBMX 3 жыл бұрын

youngjimjones hahahha🤘

@FormulaMk84 2 жыл бұрын

Cool socks, what style are they? How do you determine the low point and high point of the chain?

@jeffreyscales7891 3 жыл бұрын

Nice video man.

@BigBikeBMX 3 жыл бұрын

Thanks for watching🤘

@ekhles104 2 жыл бұрын

Very very very excellent I like it

@TheTravelVlogger 3 жыл бұрын

nice one! just got a dirtjumper/pumptrack bike and kept having issues with the back wheel moving and making the chain loose. thx

@BigBikeBMX 3 жыл бұрын

It takes a little while to get the tension right, but it's a game-changer for those annoying landings where your wheel decides to take a nasty turn and start rubbing the dropouts.

@WarrenHatton Ай бұрын

Just got my SE Racing chain tensioners for my Big Ripper. Unfortunately axle on the 2014 appears to be too short. Damn

@hawaiianpunch6534 2 жыл бұрын

I have dropout savers on my 90's Quadangle. Do I delete the washers and the chain tensioners will act as a dropout saver?

@cornnewton4804 3 жыл бұрын

Thanks for the education

@yourmom-zi2ty 3 жыл бұрын

Can u put them on a 2020bigflyer? With the pegs

@anis_vgn 3 жыл бұрын

Is that work on Big flyer ? Thanks for the answer

@wadewillson2456 2 жыл бұрын

I got a se last year and it’s so hard to align that back wheel right ima hope this helps

@danielmacatangay3571 Жыл бұрын

i got a big flyer with pegs installed and will i have to sacrifice the pegs on my big flyer to install these?

@isaactorres5908 3 жыл бұрын

I have 23 inch axle...i really need chain tensioner for it ..but they only make then for 15 mm

@renec5006 2 жыл бұрын

Put mine on last night after watching your video. Took me a while to get everything lined up the way I wanted but I think I’m good! Also one of my tensioner’s was missing the little washer that goes on the end of the tensioning bolt, don’t think it’ll affect anything though.

@BigBikeBMX 2 жыл бұрын

Those lock washer pin things always fall off. Doesn’t cause an issue with functionality though. Just remember to leave some slack or your cranks/chain/pedals will make gnarly sounds and pops.

@vice6996 Жыл бұрын

can you explain finding the high point of your chain? thanks.

@brandanbrenes1026 10 ай бұрын

Will this work on a mafia bomma 29er?

@tasoruha Жыл бұрын

Hi thanks for the great video. Wondering what's the reason for nuts tightness. Would it not be too loose so it comes off eventually? Thanks in advance!

@BigBikeBMX Жыл бұрын

Tighten the axle bolts to a normal torque and you’ll be fine. Back in the 80s we had to over-tighten to keep the wheel centered is all.

@anthonydrexler80 3 жыл бұрын

Sweet🤘

@captainnasty3031 Жыл бұрын

What up cool channel! Subbed just picked up yellow and red fat ripper. I need a set of pads. Any ideas where to get them

@BigBikeBMX Жыл бұрын

Original - Facebook groups. Sebikes.com sells aftermarket pads that match as well

@nicky2times2times10 3 жыл бұрын

I love how it sounds. What's that due to? The crank or back wheel or what makes it sound so deep?

@CenTexCollector 3 жыл бұрын

Freewheel

@85bigGMC Жыл бұрын

On the intro, what phone mount are you using to hold your phone on the bars by the grip?

@BigBikeBMX Жыл бұрын

It’s garbage. None of the ones I’ve tried will hold your phone safely yet. Let me know if you find one though🤘

@arkoutarkout3654 Жыл бұрын

So easy to to make sure you a real linked up

@brandonhunter2760 Жыл бұрын

Can you use these on an SE Fast Ripper that has a rear derailleur, and safe washer? Would you have to do anything different?

@BigBikeBMX Жыл бұрын

The axle will bend. I’d get a stronger axle if you’re adding pegs.

@juniorstarks7494 2 жыл бұрын

What exactly do chain tensioners do? I just bought the all black 29” Big Flyer. It took me a year to get it. I was on a mailing list. You’ll see me ripping around 25th Street in Ogden Utah this summer.

@BigBikeBMX 2 жыл бұрын

Chain tensioners in theory lock your wheel in place so it won’t move with extra torque when you pedal hard. I rode on the dumbest ramps and sketchy jumps in the 80s without them. They’re just nice to have

@juniorstarks7494 2 жыл бұрын

@@BigBikeBMX I just ordered mine from The Bike Barn BMX in Lehi Utah. Hopefully I’ll have no problem installing them w/the rear pegs. If so, the pegs are coming off. Thanks @Big Bike BMX

@QuebecFietser 2 жыл бұрын

would this work on a bike with multiple acesories on the rear nut assembly?

@BigBikeBMX 2 жыл бұрын

I wouldn't add pegs etc unless you have enough axle. You'll also bend the axle by extending the weight you'll add with pegs down the axle. In short, I wouldn't suggest it - but I did it on my PK Ripper.

@Jake-mo2zi 3 жыл бұрын

Can you install chain tensioners with pegs that are screw on?

@BigBikeBMX 3 жыл бұрын

Jake in theory you could as long as the axels are long enough.

@miketeiml6515 2 ай бұрын

Is it normal for the chain tensioners to not be the same on each side with the wheel centered and chain not too tight.

@BigBikeBMX 2 ай бұрын

I’ve seen it, but it’s rare. Make sure the tensioner is lined up inside the dropout and centered. I’ve had a few not seat right when they’re new. I’d also check that you haven’t twisted your frame if everything else is right.

@miketeiml6515 2 ай бұрын

@BigBikeBMX my fat quad is a pain to get them even, the quads brand new, I will attempt again today to get them even

@Tdogbikes 3 жыл бұрын

Can you use pegs with the chain tensioners on there?

@jasonwalker3477 2 жыл бұрын

I don’t think so, because there is not enough space

@robertc7931 3 жыл бұрын

Where can I get em speedy boi looking glasses they look dope af

@BigBikeBMX 3 жыл бұрын

Oakley Windjacket 2.0 - They're legit!

@leo_in_the_cut5962 2 жыл бұрын

Great video.👍 but this is useless to me because my rear axel is 14mm.🤒

@melissamowbray9482 3 жыл бұрын

I have had problems watching your old video of the GT dyno compe 29" aka Dave Volelker. It just won't let me watch it on my end so can you please repost it? Btw your really getting us old-timers on to bmx's again.

@BigBikeBMX 3 жыл бұрын

Melissa Mowbray I don’t have the original anymore. I’ll see what I can come up with though 🤘🙏

@recorddatdopeyo5561 3 жыл бұрын

Played fine all the way through for me so maybe you're on mobile or need to refresh.

@cesarsaavedra3095 2 жыл бұрын

An you run these with pegs

@_BlueCollarGamer 7 ай бұрын

what free wheel do you have on this specific bike?

@BigBikeBMX 7 ай бұрын

That was a RideOutSupply.com freewheel from 2020. They’ve updated the look to black and silver now.

@_BlueCollarGamer 7 ай бұрын

@@BigBikeBMX oh yeah I have the newer one on my Sunday high c. Just picked up this MINT 2010 Big Ripper… think I’m going to wait for theory to drop their new rattle snake freewheel. Sadly it got pushed back to November due to shipping issues and the first rounds are going to bike shops only.. got ALBES just up the road so I’m going to secure one there.

@BigBikeBMX 7 ай бұрын

@@_BlueCollarGamer Merritt & Theory are doing it right💪 - It’s hard finding that loud buzz AND still have low drag. That’s legit you live by Albes! I’d love to see that place in person

@_BlueCollarGamer 7 ай бұрын

@@BigBikeBMX their show room is awesome and there’s always something new. Real small but real dense. I can always go in there and find something to spend money on if I am bored! Lol

@user-jb2jy6tj5z Жыл бұрын

Can you run them with pegs ?

@BigBikeBMX Жыл бұрын

Always make sure your axle is long enough so the nut grabs all the threads. If it does, you can.

@tuchivlogs2062 Жыл бұрын

Can I use this for my gts bike ?

@BigBikeBMX Жыл бұрын

Yes

@grandd5913 Жыл бұрын

I’m looking for a good cell phone holder any suggestions?

@BigBikeBMX Жыл бұрын

I’ve tried quad lock and it didn’t work for me but I’ve heard bikebaggie works well. It’s a top tube bag with a phone sleeve. Let me know if you find something that works!

@miketeiml6515 2 ай бұрын

The fat quad is the hardest to get aligned with the chain tensioners, trying to get them even side to side is a pain it the butt

@Zombie123 2 жыл бұрын

"I like to ride my bike" 🤣

@focused40 2 жыл бұрын

Is it possible to have chain tensioner and pegs on a bike?

@BigBikeBMX 2 жыл бұрын

As long as your axle is long enough. You’ll want to make sure you can see the axle though the bolt inside the peg. It works on my PKRipper 27.5 but not my Big Flyer for example.

@briancatena4152 2 жыл бұрын

This may be a stupid question but do you need chain tensioners on a fast ripper?

@BigBikeBMX 2 жыл бұрын

Great question. Fast rippers are geared so that mechanism handles chain tension. Geared bikes don’t have normal BMX dropouts.

@aka_aadam9552 3 жыл бұрын

Aye are chain tensioner a compatible with pegs

@BigBikeBMX 3 жыл бұрын

Always depends on if there’s enough axle left after adding both tensioners and pegs. Put them on and tighten the axle bolts - if there’s still axle sticking out of the nut, you’re good. Remember, if your bike didn’t come with them, it could void the warranty. I don’t blame SE or the bike company if I bend something though. I modified the bike and I own the outcome🤘

@508_ryan6 3 жыл бұрын

If I put these on with my pegs is that a bad idea?

@BigBikeBMX 3 жыл бұрын

It always comes down to how long your axels are. The tensioners take up threads... then pegs take threads... so you want to make sure with both installed, you have enough thread that the axel nut completely covers the axels. I know SE doesn’t suggest it and it might void warranty. Unless you bike came with both, I wouldn’t do it. If you have to choose, go with pegs if you’re doing wheelies and footwork.

@SpacedzOutt 9 ай бұрын

Can I do it on my fast ripper

@BigBikeBMX 9 ай бұрын

Nope. Fast rippers use a derailleur to keep your chain tight flipping through gears. It has a vertical dropout that fixes the axle in place. Chain tensioners work on horizontal dropouts and pull your wheel back to create chain tension.

@bradleypfeffer1716 3 жыл бұрын

I know I'm off subject, but why do you think the Monster quad isn't as popular as the Ripper? Is their any cons about the bike ?

@BigBikeBMX 3 жыл бұрын

Cons about the Monster Quad? None. If the monster quad was available when I was looking - this would be a monster quad in the video. I love them. I think rippers are more cost-effective and so you see more of them. Also, they’ve been doing big rippers a lot longer.

@bradleypfeffer1716 3 жыл бұрын

@@BigBikeBMX thanks bro💪

@bradleypfeffer1716 3 жыл бұрын

Just ordered it🥳

@BigBikeBMX 3 жыл бұрын

@@bradleypfeffer1716 It's a badass bike bro. Tag me on Instagram when you get it! @bigbikebmx on Instagram.

@cstalley 3 жыл бұрын

Glad you asked this. I bought a Monster Quad a couple of weeks ago and I love it but was wondering the same thing, why aren't they as popular. Anyway mine is in the shop getting bigger bars, new freewheel and tires. I missed riding it this weekend. I think you'll really like it.

@SuperJbro 3 жыл бұрын

Can you still use pegs with that on ???

@BigBikeBMX 3 жыл бұрын

Depends on the axle length. On my stock big ripper - no. On my stock PK ripper - yes. You'll want to make sure you have enough tread on the axle to have both a tensioner and a peg and have the axle nut bolt down and grip all the threads. Good luck.

@bigcatz74 2 жыл бұрын

Can you use just for show ?

@BigBikeBMX 2 жыл бұрын

you could, but if you're putting them on for show - take the two minutes to adjust them. Its easy.

@luke8343 3 жыл бұрын

The plate inside my chain tensioner won’t back out

@tylerhoeffner8242 3 жыл бұрын

Does this work with pegs also?

@BigBikeBMX 3 жыл бұрын

Depends on the axle length after you put them on. It’s not suggested, but I’ve seen it work

@munnymakerz1375 3 жыл бұрын

Is it possible to uninstall chain tensioner ?

@PumaM90 2 жыл бұрын

Chain tensioners are like herpes. Once your bike gets them they ain't never coming off.

@CSRAAW 2 жыл бұрын

What freewheel are you using?

@BigBikeBMX 2 жыл бұрын

Probably RideOutSupply. It’s been awhile since I filmed this one

@joeyspindler7858 Жыл бұрын

Can i add this on my mountain bike

@BigBikeBMX Жыл бұрын

The derailleur on a mtb keeps your chain nice and tight. These are for single speed bikes with horizontal dropouts🤘

@creesrandom5528 2 жыл бұрын

Same thing on a Big Flyer with pegs?

@BigBikeBMX 2 жыл бұрын

Yes. Just make sure your axels are long enough👍

@joshuawhite8699 3 жыл бұрын

Yes. Brakes.

@droc85ncm 3 жыл бұрын

Brakes please. Mines grind against the rims n slows the tire down. Pls show us

@BigBikeBMX 3 жыл бұрын

I made one for calipers and show some brake tuning in the fat quad build👍

@jasonrowe9224 3 жыл бұрын

Hey Issac how you goin you can can call me JAY . Jason Rowe is way to formal for me bro . I totally get what you say about your bike being a tool just like a surfboard a skateboard a tennis racquet but me personally I love having the BIGGEST BEST LOOKING BADASS ride on the block and my kids stranger things goose is the conversation starter with old BMXERS until they realise the monster is a modern quadrangle I will send photos when it’s done

@BigBikeBMX 3 жыл бұрын

Can’t wait to see it!

@ygfromig 2 жыл бұрын

can you still have pegs with these?

@BigBikeBMX 2 жыл бұрын

If there's enough axle length - technically, yes. It'll void your warranty though. Adding pegs means you're standing/jumping on them like you should be. You're adding extra weight futher down the axle so it'll bend faster than if you didn't have chain tensioners. Hope that helps explain why it could work, but why you shouldn't do it.

@regitron3873 3 жыл бұрын

What freewheel is that?

@BigBikeBMX 3 жыл бұрын

This is an Origin 8 Hornet. I like the RideOutSupply freewheel more though. They both have high engagement, but the RideOutSupply freewheel is better though.

@gioserje2952 3 жыл бұрын

Isaac Irvine I’m getting my free wheel in the mail today

@AlpineFall1971 Жыл бұрын

The glasses are because it’s hot? Did I hear that correctly? I can’t believe SE actually put their name on them.😂

@johanthandelgado2282 3 жыл бұрын

Does any one know how to put pegs on a Pk ripper

@Asphaltsquadron 3 жыл бұрын

By high point and low point, you are referring to the chain's tension, correct? Which is high and which is low (taught/loose?) can you elaborate please? I've always noticed it changes when you rotate the sprockets. I used to think it was a stretched chain on my Harleys and dirt bikes, but now I've noticed brand new chains are like that. Just installed two on two brand new project bicycles and they both do that, so I adjusted to a happy medium about 1/2" play +/- On a side note, I used to have a pair of Oakleys like that in the early 90s for snow skiing. They were white frames and purple iridium lenses. Dope! OH YEAH, BROTHER! I just subscribed.

@BigBikeBMX 3 жыл бұрын

MrAsphaltSquadron you’re 100% right. High is taught and low is loose. Every bike has it. Sounds like you have it adjusted at the right spot too.

@Asphaltsquadron 3 жыл бұрын

@@BigBikeBMX Thanks, Brother!

@user-wr7ho4rj5v 3 жыл бұрын

Why do you need 1 on each sides??

@andreyarista4916 3 жыл бұрын

1 to tighten the chain and 1 to straighten the wheel

@c._swerve2379 3 жыл бұрын

Can I still have my pegs on my bike with a chain tensioner on?

@BigBikeBMX 3 жыл бұрын

C._swerve 23 it depends on how long the axel on your wheel is. Good example: my big ripper no. My PK ripper can🤘

@anhthonyy 3 жыл бұрын

Isaac Irvine would it fit a big flyer you think?

@c._swerve2379 3 жыл бұрын

Oh I have the big flyer so I’m hoping it does

@BigBikeBMX 3 жыл бұрын

okAnthony I honestly don’t know. I haven’t seen how long the axels are on the Flyer. I’d ask your local shop before you buy🤘

@BigBikeBMX 3 жыл бұрын

C._swerve 23 I’d ask your local shop before you buy. They’ll tell you if you have enough axel length for both

@ShesComplicated 3 жыл бұрын

what if i only put one ?

@BigBikeBMX 3 жыл бұрын

Vincen Casas not sure that will work. You need even tension

@marcellocano1311 3 жыл бұрын

What about with pegs?

@BigBikeBMX 3 жыл бұрын

That depends on your individual bike and how much axle you have left after adding chain tensioners.

@marcellocano1311 3 жыл бұрын

@@BigBikeBMX I have a 18’ big ripper so it should prolly be the same amount as yours

@BigBikeBMX 3 жыл бұрын

@@marcellocano1311 I would say test it. Put the chain tensioners on and see how much is left over. If you have enough thread to put the pegs on and STILL have some thread popping out the axle nut, you should be ok. Now, that being said... It's not designed to have both so ride at your own risk - but that's what I do with pegs and chain tensioners.