650B and frame front center

[esldude]

I have read a few renowned frame designers comment upon the importance of proper front center. 590 or 595 mm often being mentioned for road bikes. I do realize on bike frames you change anything then you change everything. Or as e-Richie puts it, in a gestalitic way, "the frame is the frame".

So I was wondering, if you built a road frame for 650B wheels, what front center works? For weight distribution are you still looking for a 590'ish front center or do you need something else?

[Mark McM]

I have read a few renowned frame designers comment upon the importance of proper front center. 590 or 595 mm often being mentioned for road bikes. I do realize on bike frames you change anything then you change everything. Or as e-Richie puts it, in a gestalitic way, "the frame is the frame".

So I was wondering, if you built a road frame for 650B wheels, what front center works? For weight distribution are you still looking for a 590'ish front center or do you need something else?

The front center should be the same for the same intended usage (e.g. road riding) - especially if the purpose of the 650b wheels is for the use of fat tires, which result in a total wheel diameter not much different from skinny 700c tires.

[Chance]

I have read a few renowned frame designers comment upon the importance of proper front center. 590 or 595 mm often being mentioned for road bikes.
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News to me. Seriously, never read this before. Would think front center would have to vary significantly by bike size.

[Mark McM]

News to me. Seriously, never read this before. Would think front center would have to vary significantly by bike size.

Yes, it can vary with both frame size and intended user/usage. For example, the Front Center of the Specialized Tarmac varies from 576mm (size 49) to 612mm (size 61), while on the Specialized Roubaix it varies from 582mm (size 49) to 643 (size 61). Both of these bikes are 700c wheel road bikes, but they have different geometries reflecting different fit and intended usage.

[esldude]

I have seen comments from Grant and e-Richie that both indicate they don't go much below 590 mm for front center for the former and 595 mm for the latter. I may be reading too much into such comments. But I believe both have favored maintaining that and altering trail and HTA to maintain it over different sized frames. I also believe I recall they may let FC go up on larger frames above that number.

And I am not trying to boil frame design down to one magic number which is hopeless. Just curious how FC might be altered for the smaller wider tires by such designers. I am thinking they would leave it the same.