How to determine if a wheel/tire combo fit with a given frame

[cyan]

What are the measurements I need to take off a frame to determine if a (clincher) wheel/tire combo fits? My frame recommends 25mm tire width, but it doesn't say anything about the rim.

For the wheel/tire, I guess I need: max width and bead width of the rim, the tire width (looking at 25mm or 28mm). I understand that some tire will be wider and higher than others, and the tire width and height also depend on the rim. Without having the wheel/tire in hand and actually trying it, how can I estimate as accurately as possible.

[Ken Robb]

If the manufacturer says 25 I think you will be lucky to fit 28 and I wouldn't make any commitment to that size without a trial fit of the wheel/tire combo you want to use.

[oliver1850]

Many complete bikes come with 23 mm tires but will fit 28s. There's a good chance someone here knows what will fit yours, so tell us what the frame and fork are. If that angle doesn't work I'd try to find someone local with the tire size (and brand if possible) you want to run mounted up and give it a trial fit. Just find the local bike geek. For example, I'm sure I have 700c tires mounted up in 18, 20, 23, 25, 26, 28, 30, 32, 35, and 38 mm widths.

[cyan]

Many complete bikes come with 23 mm tires but will fit 28s. There's a good chance someone here knows what will fit yours, so tell us what the frame and fork are. If that angle doesn't work I'd try to find someone local with the tire size (and brand if possible) you want to run mounted up and give it a trial fit. Just find the local bike geek. For example, I'm sure I have 700c tires mounted up in 18, 20, 23, 25, 26, 28, 30, 32, 35, and 38 mm widths.

Frame set: Seven Axiom SL with Enve 2.0 tapered 43 rake fork.
Wheel/tire combo: Zipp 202 Firecrest with Continental GP 4000 S II (25mm or 28mm)

The Enve fork is a bit confusing, some resellers list it with up to 28mm tire clearance, whereas the specs on the Enve official website says 25mm max.

[sokyroadie]

The Enve fork is a bit confusing, some resellers list it with up to 28mm tire clearance, whereas the specs on the Enve official website says 25mm max.

All Enve 2.0 forks I have used will clear a 28 no problem.

[R3awak3n]

Yeah i have never seen an enve 2.0 that doesnt clear a 28mm (that measures 28-29mm)

[Peter P.]

For sure, rim width can affect an inflated tire's profile, and one manufacturer's 28mm tire will not measure the same as another manufacturer's tire.

The only surefire way to tell whether you've got the clearances is to buy and try.

I'd love to see some photos of 28mm tires through carbon forks; in many instances the clearances are so negligible that the slightest debris stuck on the tire or slightly out of true wheel makes it a no-go.

Between carbon fork restrictions and brake arm design, compatibility issues seem to be a frequent problem.

[happycampyer]

Brake caliper clearance matters, too. Not sure about the latest iteration (2018), but Campagnolo calipers sit lower than Shimano calipers (not sure about SRAM).

I think Enve publishes clearance for 25mm tires and not 28mm because 27 - 28mm tires are hit-or-miss—there are too many variables (tire profile/height; rim width; brake caliper; etc.) to say that a wider tire will fit. Ultimately, the road fork was designed when 23 - 25mm tires were standard.

Bear in mind too that the most supple 25mm tires ride better than many 28mm tires...

Someone should start a “brake clearance combo” thread, or revive an older thread and keep it going...

[happycampyer]

Here’s a thread from way back—see my photos on page 2.

https://forums.thepaceline.net/showthread.php?t=122464

I would also note that it’s interesting that the Seven has an Enve fork and not a Seven fork. The Seven road fork has way more clearance then the Enve.

[cmbicycles]

Do you have any wheels/tires to eyeball in the frame? That would give you an idea of how much space you may have to work with.

Do you know what rims you will be using? Someone with those rims could easily give you some dimensions of tires they are using.

[Mike Bryant]

I tried Conti GP4000s 25 and 28 on Zipp 202 Firecrest wheels. The 25s fit in an older Edge (Enve) 2.0 fork with a straight steerer. 28s would not. Too tall. The Conti 28s do fit in a Reynolds Ouzo Pro.
Vitoria Corsa Graphene 28s on the Zipps fit in the Edge fork.

Dura Ace 9000 brakes.



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[Peter P.]

Ultimately, the road fork was designed when 23 - 25mm tires were standard.

The real problem was the market switch from steel forks to carbon forks.

To retain the necessary strength, carbon forks need larger cross-section crowns and larger fork blades than steel forks. That reduced any tire clearances. Since steel forks set the standard for axle to crown lengths with short reach brakes set to mid-slot (approx. 44mm), replicating that dimension with a carbon fork pushes the limits of tire compatibility.

One solution would be for frame manufacturers to build frames around a short reach brake's maximum reach (approx. 49mm) and fork manufacturers to build their forks accordingly. A second solution would be the scenario above but build forks around a normal reach front brake (47-57mm) at mid-slot, leaving the rear brake unchanged. It can be done but the weight weenies will protest the caliper and longer fork weigh more!