29.8mm v 30mm seattube clamp

[martint235]

So as you may have seen from another thread, cackhanded Martin paid a visit yesterday and I snapped a seat tube clamp, it may have been fatigued anyway and could have been the cause of the noise I'm trying to fix but anyways.

So 29.8mm clamps seem fairly rare but I've found a 30mm Hope one that looks like it will do the job, is that 0.2mm really going to be an issue? 2mm doesn't sound like much let alone 0.2mm.

Advice please?

 

[Yellow Saddle]

Yes, it will make a difference and is not suitable. Hunt for the right clamp.

The clue lies with Pie. The circumference of a 29.8mm dia circle is 93.62mm and that of a 30mm circle is 94.25. The difference is enough to make the clamp ends touch before it has clamped enough.

 

[djb1971]

The 30mm hope I use replaced a 29.8mm and my post slips, every ride. This is using a Thomson post, which are prone to slipping.

The Hope clamps don't let you over clamp too much so you can't get it to grip. I'm trying carbon paste this weekend to see if it helps with the 30mm issue.

 

[djb1971]

All of my other bikes have Thomson clamps, theyre perfect. Unfortunately they were out of stock in 29.8mm.

 

[r04DiE]

So as you may have seen from another thread, cackhanded Martin paid a visit yesterday and I snapped a seat tube clamp, it may have been fatigued anyway and could have been the cause of the noise I'm trying to fix but anyways.

So 29.8mm clamps seem fairly rare but I've found a 30mm Hope one that looks like it will do the job, is that 0.2mm really going to be an issue? 2mm doesn't sound like much let alone 0.2mm.

Advice please?

Shim it with beer can?

 

[Yellow Saddle]

Shim it with beer can?

Beer can is too thick.

 

[r04DiE]

Beer can is too thick.

Stella beer can isn't

 

[Sharky]

Try searching for a shim. One of mine, a Giant Bowery came with a standard seat post (27.2) and a plastic shim to fit inside the seat tube. Works fine with no slipping.

 

[Sharky]

https://www.evanscycles.com/use-shi...esvaid=50080&gclid=CO7es-7cqNICFQuNGwodsncP1Q

 

[martint235]

https://www.evanscycles.com/use-shi...esvaid=50080&gclid=CO7es-7cqNICFQuNGwodsncP1Q

Thanks but those are to shim a 27.2mm post up to varying sizes. I've only got a 0.2mm difference so doubt I'll get a shim for that.

 

[Yellow Saddle]

Stella beer can isn't

I'll be surprised if Stella uses a can that's different from the industry norm.
Aluminium cans are usually 0.12mm thick. That's just too much for the 0.1mm that you need to shim the clamp. Although.02 may not sound like much and can easily be "absorbed" by the clamp, it will require a bit of stretching open and then, not clamp nicely around the tube and pleat the shim.
Nice brass shim stock can be had in 0.1mm and will do a better job. The best still is the right clamp since installing a shim in there is a bit fiddly.

But just to prove that I'm not too set in my beliefs, I shall go out and buy several Stellas and check the can thickness. I'll average it out over say 12 cans?

 

[Sharky]

Thanks but those are to shim a 27.2mm post up to varying sizes. I've only got a 0.2mm difference so doubt I'll get a shim for that.

The Evans site does seem to list a shim for a 29.8mm?

 

[r04DiE]

I'll be surprised if Stella uses a can that's different from the industry norm...

 

[martint235]

The Evans site does seem to list a shim for a 29.8mm?

My understanding of it is it's to shim a 27.2 seatpost into a 29.8 seat tube? I could easily be very wrong.

 

[martint235]

I'll be surprised if Stella uses a can that's different from the industry norm.
Aluminium cans are usually 0.12mm thick. That's just too much for the 0.1mm that you need to shim the clamp. Although.02 may not sound like much and can easily be "absorbed" by the clamp, it will require a bit of stretching open and then, not clamp nicely around the tube and pleat the shim.
Nice brass shim stock can be had in 0.1mm and will do a better job. The best still is the right clamp since installing a shim in there is a bit fiddly.

But just to prove that I'm not too set in my beliefs, I shall go out and buy several Stellas and check the can thickness. I'll average it out over say 12 cans?

Not scientific enough. I'd say 48 but at least 24. You have all weekend