XT 732/735 Front Derailleur Size

[Atmos]

Ok, i have a problem here. I been looking in ebay to buy a XT 732/735 Front Derailleur for a new build which takes a 28.6 front. I have since purchased twice from ebay and both came to be 26.8 when it arrived. Both sellers listed them as 28.6 (size was not stamp on the derailleur) but i measure them at 26.8 when close fully. Recently i approached a 3rd ebayer which also listed his derailleur as 28.6. This time, i was clever and ask him to measure it and take a photo for me to confirm if its correct. Luckily i did as it turns out to be weird as well (refer to photo). My question is do they come in 28.6? According to the manual, the smallest is 28.00-28.6 but when measured it is 26.8! What am i missing here? Did anyone encountered this issue before, please kindly enlighten me. It is frustrating and im still trying to source for a correct one. TIA

 

[hamster]

They look like normal 28.6 to me. The clamp is never fully closed. I think Shimano's design factors in a little flex in the clamping band to avoid pinching and denting the tube near the clamp bolt position.

 

[Atmos]

They look like normal 28.6 to me. The clamp is never fully closed. I think Shimano's design factors in a little flex in the clamping band to avoid pinching and denting the tube near the clamp bolt position.

Hi Hamster, the gap shown is normal? As i think it is a little too wide and the bolt thread just went in a little.

 

[mk one]

The clamp cant close fully as it needs to tighten down on the tube, i assume the difference is to accommodate differences is thicknesses of different tubes.

The best method is to attach the mech to the frame, if you can fully tighten it and its still loose then its too small, if the tube is too big the clamp will not go round and you will not be able to put bolt in.

 

[hamster]

They look like normal 28.6 to me. The clamp is never fully closed. I think Shimano's design factors in a little flex in the clamping band to avoid pinching and denting the tube near the clamp bolt position.

Hi Hamster, the gap shown is normal? As i think it is a little too wide and the bolt thread just went in a little.

Looks right. The clamp is designed to bend slightly and fit evenly around the seat tube on tightening. Otherwise it wouldn't grip.

You are over-thinking this.

 

[FluffyChicken]

Re:

They are 28.6

smaller sizes were never made as there were never tubes that thin.

Just fit it

 

[Atmos]

The clamp cant close fully as it needs to tighten down on the tube, i assume the difference is to accommodate differences is thicknesses of different tubes.

The best method is to attach the mech to the frame, if you can fully tighten it and its still loose then its too small, if the tube is too big the clamp will not go round and you will not be able to put bolt in.

I understand that the clamp cant close fully but it shouldnt be that big gap too. I did tried it on my frame and the gap is big. The bolt can go in a couple of turns. I measured my tube at 28.6...

 

[Atmos]

They look like normal 28.6 to me. The clamp is never fully closed. I think Shimano's design factors in a little flex in the clamping band to avoid pinching and denting the tube near the clamp bolt position.

Hi Hamster, the gap shown is normal? As i think it is a little too wide and the bolt thread just went in a little.

Looks right. The clamp is designed to bend slightly and fit evenly around the seat tube on tightening. Otherwise it wouldn't grip.

You are over-thinking this.

I hope i am as this is the 1st time i encounter this issue.

 

[Atmos]

Re: Re:

They are 28.6

smaller sizes were never made as there were never tubes that thin.

Just fit it

haha i thought i was real unlucky to have met 3 ebayers who advertise wrongly on them.
Thanks for the clarification!

 

[FluffyChicken]

Re:

As a side the clamp bolt is 15mm long if original.

You sometimes find bikes where the paint bunches up between the clamp ends.

So you now need to find two more frames to put the other front mechs on ;-)