READ: Chainstay Clamps PSA and PRO Tip

[Robert Holler]

Ok all - I go over this in all of the assembly videos but it seems to me missed way too often:

Please DO NOT OVERTIGHTEN your chain stay clamps. Every time I see a broken one it is the same pic - the surfaces are mated completely against one another - that is TOO tight and if you do this - they WILL break.

I am posting this because currently we are OUT of spare chain stay clamps. More will be coming - but if you want to be riding this summer - DO NOT OVERTIGHTEN these clamps.

Maria, Jim, Myself, and a lot of others have hundreds if not thousands of miles and many years of riding the same clamps - so they are not necessarily a weal juncture. I am using the non-anodized raw aluminum sample ones for the last 4 years with no issues. Because they are never overtightened.

When tightening - there must be an EVEN gap on both sides - just like a handlebar clamp. Then when they get just snug - they only need to be 1/4 to 1/2 turn past JUST SNUG to be tight enough. If one or the other or both of the surfaces of the clamps are touching - they are overtightened. You should be able to put a credit card thickness or a bit more between the clamp and stay surfaces at both faces.

 

[benphyr]

@Robert Holler (2019 S40) Can you advise on troubleshooting the boom wanting to not be lined up straight with the frame? I tighten chain stay clamps evenly, then boom clamp, then slider/headset clamp, then tighten quick release and the quick release clamp applies a torque to everything. If I then loosen the slider clamp again the boom shifts over to the driver's side maybe 5 mm. What am I doing wrong?

 

[ak-tux]

Ok all - I go over this in all of the assembly videos but it seems to me missed way too often:

Please DO NOT OVERTIGHTEN your chain stay clamps. Every time I see a broken one it is the same pic - the surfaces are mated completely against one another - that is TOO tight and if you do this - they WILL break.

I am posting this because currently we are OUT of spare chain stay clamps. More will be coming - but if you want to be riding this summer - DO NOT OVERTIGHTEN these clamps.

Maria, Jim, Myself, and a lot of others have hundreds if not thousands of miles and many years of riding the same clamps - so they are not necessarily a weal juncture. I am using the non-anodized raw aluminum sample ones for the last 4 years with no issues. Because they are never overtightened.

When tightening - there must be an EVEN gap on both sides - just like a handlebar clamp. Then when they get just snug - they only need to be 1/4 to 1/2 turn past JUST SNUG to be tight enough. If one or the other or both of the surfaces of the clamps are touching - they are overtightened. You should be able to put a credit card thickness or a bit more between the clamp and stay surfaces at both faces.

Thanks Robert.

Maybe in the future there should be :

1. a set of four spring washers included (one for each bolt) between the clamps and the chainstay to limit the minimum gap possible.
2. A torque setting printed on the clamps for those who have a torque wrench to refer to.

 

[Robert Holler]

@Robert Holler (2019 S40) Can you advise on troubleshooting the boom wanting to not be lined up straight with the frame? I tighten chain stay clamps evenly, then boom clamp, then slider/headset clamp, then tighten quick release and the quick release clamp applies a torque to everything. If I then loosen the slider clamp again the boom shifts over to the driver's side maybe 5 mm. What am I doing wrong?

Hmmm I am not sure how this would be happening as long as the stay/fork/boom are aligned "neutral" before tightening in order skewer, then stay clamps and making sure the pivot clamp is aligned right.

 

[Robert Holler]

Thanks Robert.

Maybe in the future there should be :

1. a set of four spring washers included (one for each bolt) between the clamps and the chainstay to limit the minimum gap possible.

This is a great idea.

 

[Beano]

Thanks Robert.

Maybe in the future there should be :

1. a set of four spring washers included (one for each bolt) between the clamps and the chainstay to limit the minimum gap possible.
2. A torque setting printed on the clamps for those who have a torque wrench to refer to.

I'd second this, speaking of which anyone know of the torque settings?

 

[Beano]

I'd second this, speaking of which anyone know of the torque settings?

Just had another look at this taking on board what Robert said above.

I used two credit cards whilst initially tightening the bolts until they touched the credit cards. And then evenly tightened each bolt to what is imo 'Just snug'. Adding another quarter turn to this gives a torque setting of 2nm. I cannot fit two credit cards in the gap that is left but one will go freely.

 

[Robert Holler]

Bumping this PSA - don't over tighten the clamps. Don't over tighten the clamps. Don't over tighten the clamps. Don't over tighten the clamps! These are very low supply and there is zero reason they should break if they are not overtightened. I have never broken one is many years of riding and adjusting my bikes. If the surfaces are mated together you have already made them WAY too tight.

Less is more.

That is all.

 

[Merczak73]

I have put in washers, as suggested above. Regular washers work great (as opposed to lock washers) to not over tighten the clamps, BTW. Depending on the type of washer (thickness), you might need two on each screw/clamp area to not over tighten the clamps.

 

[SHAHROM]

IMO it's easier to be precise on ANY settings, especially when there is evidence of broken parts. Ak-Tux's suggestion is good, and should be adopted by CB.

ps
The fineprints of torque settings on critical parts is actually a nice artform, and should look nice on any CB.

 

[BikeGary]

I'd second this, speaking of which anyone know of the torque settings?

I'll second this. I have a torque wrench so I can set it correctly... And will double check mine tonight.
Ok, checked the spacing and it was a tad tight on one side, perfect on the other. Backed off a 1/4 turn or so and it's set. Thanks Robert.

 

[BranchRider]

Thanks Robert.

Maybe in the future there should be :

1. a set of four spring washers included (one for each bolt) between the clamps and the chainstay to limit the minimum gap possible.
2. A torque setting printed on the clamps for those who have a torque wrench to refer to.

Robert, I appreciate your support and advice, but the pair of chainstay clamps that just failed (one brok and the other is cracking) on my 2020 Q45 were not mated to the other side. I had torqued them to 4 Nm as advised but they failed anyway. Maybe the failure of the second was hastened by the failure of the first one, but the fact remains that the clamps are a weak point in the design of a product that relies on the end-user to assemble without an objective torque spec (now the torque spec seems to be "just snug" plus 1/4 to 1/2 turn). I just ordered another set of clamps ($75!) and I hope they'll come with the spring washers that you said three years ago would be a good idea. And I hope that my idea of "just snug" is the same as yours.

 

[ak-tux]

Robert, I appreciate your support and advice, but the pair of chainstay clamps that just failed (one brok and the other is cracking) on my 2020 Q45 were not mated to the other side. I had torqued them to 4 Nm as advised but they failed anyway. Maybe the failure of the second was hastened by the failure of the first one, but the fact remains that the clamps are a weak point in the design of a product that relies on the end-user to assemble without an objective torque spec (now the torque spec seems to be "just snug" plus 1/4 to 1/2 turn). I just ordered another set of clamps ($75!) and I hope they'll come with the spring washers that you said three years ago would be a good idea. And I hope that my idea of "just snug" is the same as yours.

For my case, (a 2019 S40) they also had started cracking but I inserted some 4 washers ( one for each bolt, between the clamps and the chainstay) that I got some from an old road bike stem. I tightened them using a torque wrench to I think about 4Nm if I remember corrrectly.

It has stayed put since then and the cracks did not progress.

 

[BranchRider]

For my case, (a 2019 S40) they also had started cracking but I inserted some 4 washers ( one for each bolt, between the clamps and the chainstay) that I got some from an old road bike stem. I tightened them using a torque wrench to I think about 4Nm if I remember corrrectly.

It has stayed put since then and the cracks did not progress.

Thanks, ak-tux! If the new bolts don't come with washers, I'll find some.

 

[Sketch44]

60 Dollars and 15 in shipping for 4 tiny pieces of metal.....SMH. This is ridiculous.

 

[Sketch44]

60 Dollars and 15 in shipping for 4 tiny pieces of metal.....SMH. This is ridiculous.

Thank you to Cruz for the handwritten note explaining the challenges of part supplies for small manuf and the small gift. I will add that the new part comes with washers to prevent overtightening which I also really appreciate.