Custom Titanium Options

[Jeff N.]

It always puzzles me how some custom Ti frame builders are limited with certain options. For example, some frame builders only offer 27.2 or 30.9 seat post sizes (Caletti, Firefly, No 22, Moots) while others offer 31.6 (Mosaic, Holland, et.al.). Same thing with internal rear brake cable routing. Seems to me that all these high-end builders could/should offer these and all options. What's the limiting factor? Thoughts?

[tuscanyswe]

If i recall correctly..

I was told by an upscale brand that 31.6 diameter tubing were not done in a large enough scale to a good enough quality so the they did not think it was a good option for use in seatposts.

Bs or not. I dunno .)

[eddief]

more inventory = more dead money.

Maybe the 80/20 rule applies?

[Ken Robb]

How much experience is required for a builder to become really skilled with a type/size material and/or technique? Some custom builders may want to stick with the things they have mastered and they may not feel that offering buyers more options won't improve the final product.

SOME (not all) builders may feel that offering many options is part of the mystique that leads people to order custom frames even if the builder knows some of the options won't improve the final product. Surely some very good builders tell customers something like "just tell me how you want the bike to perform and leave the design details to me."

[sandyrs]

I see no reason a builder who has plenty of business should feel compelled to offer options they don't consider worthwhile, either for the rider or for themselves.

[Black Dog]

Originally Posted by tuscanyswe

If i recall correctly..

I was told by an upscale brand that 31.6 diameter tubing were not done in a large enough scale to a good enough quality so the they did not think it was a good option for use in seatposts.

Bs or not. I dunno .)

Hmmmm... Litespeed does 31.6 in Ti. The OD is standard 34.9.

[tv_vt]

Don't know. Could also tie into their build philosophy.

I know Eriksen only does 27.2 ID seat tubes, or almost 'only'. Certainly doesn't hurt the ride at all.

Ti is for sure harder to work with than steel.

[Mikej]

Originally Posted by tv_vt

Don't know. Could also tie into their build philosophy.

I know Eriksen only does 27.2 ID seat tubes, or almost 'only'. Certainly doesn't hurt the ride at all.

Ti is for sure harder to work with than steel.

Depends on the size- there are 30.9 Eriksen bikes out there. Friend had one nd it was sooo bumpy for my 155 lbs body.

[zank]

Sizing the ID of a seat tube for a seat post is generally done in one of two ways. One way is to glue a composite shim and the other way is to weld in a thicker extension. Generally speaking with 34.9 mm seat tubes, the shim works well with 27.2 (nice because just about every post comes in 27.2) and the weld in works well with 31.6 (nice because you don't need to weld in a thicker extension to reduce to 27.2). Note that there are exceptions.

Not all builders want to add more heat to a tube than what is necessary and some builders feel very strongly about not wanting to pierce a tube. Any weld invites contamination and there is risk involved with expensive material. It's similar to the topic that pops up often about weld-in vs riv nut bottle mounts.

Each builder/company has their own philosophy and comfort level. Having observed and been a part of this niche for a long time, I can say that a lot of marketing speak has been written because a company doesn't want to do something. This is especially true about titanium.

[David Kirk]

So....is the idea that all builders should offer the same options?

dave

[Pegoready]

What bike are you planning next?

[Mark McM]

From a rider/owner perspective, what are the practical implications of 27.2mm vs. 30.9mm vs. 31.6mm seat post diameters?

[tommyrod74]

Originally Posted by Mark McM

From a rider/owner perspective, what are the practical implications of 27.2mm vs. 30.9mm vs. 31.6mm seat post diameters?

27.2 allows for more seatpost flex (especially given a lot of exposed seatpost and/or setback) and therefore more seated comfort. Maybe better for smaller/lighter riders.

Larger diameters allow for a stiffer seat tube and theoretically a stiffer frame - bigger interface with BB shell, top tube, etc. Maybe a plus for larger/more powerful riders. Also - easier to find dropper posts in 31.6.

Of course, there are other ways to build in stiffness or compliance.

[Clean39T]

Originally Posted by tommyrod74

27.2 allows for more seatpost flex (especially given a lot of exposed seatpost and/or setback) and therefore more seated comfort. Maybe better for smaller/lighter riders.



Larger diameters allow for a stiffer seat tube and theoretically a stiffer frame - bigger interface with BB shell, top tube, etc. Maybe a plus for larger/more powerful riders. Also - easier to find dropper posts in 31.6.



Of course, there are other ways to build in stiffness or compliance.

When it comes to stiffness, it isn’t just about size - it’s how you use it... amiright???

[Kontact]

I would be appalled if custom builder's agreed to build every which way and had no opinions on how some things should be done. That kind of ambivalence to design is what Chinese weld shops are for.