Silver_Nettle

Hello-- I recently bought a new Diverge and had the shop, per their recommendation for a race tire, put a pair of tubleless tires on ( Tracer 38c).

Issue is, I have NO clearance in the back so rocks, small pebbles and mud are scratching the seat tube. I am a bit confused because this is well within what Specialized states it can fit (even if it inflated over the actual stated size).

What are folks running in the back of their Diverage and shouldn't the shop make this right since I dropped $55 on the tire plus the $$ for the tubeless conversion.

**also it won't let me post a photo, but my flickr name is: silver_nettle

Marcus_Ti

Sucks, amigo. A few things:

A) Tire clearance is typically stated in "you'd better not get gravel back there" terms.

B) Tire clearance depends on the wheel-rim, wider rims can cause tires to run wider than true to width. Have you measured your 38mm tires to see if they actually are running true to rated size?

Silver_Nettle

I don't have calipers to measure, but the Diverge is supposed to accept up to 42c tires so the 38's should fit even they run big?

tyCycler

The stock trigger pro 38's (measured at 37mm with digital calipers at 50psi) on my Diverge Expert seem to have plenty of clearance. Which model of the Diverge do you have, because the alloy versions do not accept as large if I recall.

Silver_Nettle

The Diverge E5 Elite.

At this point I'm not even sure if 35's would give enough clearance. Check the photo on Flickr if you have a moment.

Not sure why the shop would have suggested these knowing it's the alloy frame. Pretty ticked off at this point.

Jofu

Hello Silver,

Just a thought, but is this a new model (2018) Diverge, or a "new" 2016-or-older model Diverge? Up to 42c tires is for the former. My 2016 for example barely takes a 33c.

Geoff

Silver_Nettle

It's a 2018 (not the carbon model) so it should take 38 tires per Specialized.

Garfield Cat

Will any Diverge accommodate the 650 wheels?

Silver_Nettle

The BB is already low enough, 650b would not be something I would be interested in.

RideMyLeMond

According to Specialized, only the Carbon frame can accommodate 650 wheels. The usable tire sizes they state as;
650 x 47 = Good
650 x 45 = Marginal

Sal Bandini

My 32c tires on my Sirrus measure around 38 so I have little faith in tire-numbering system. I agree they should make it right.

And pardon the noob question, but why would all 700c disc frame bikes not accept a 650b tire?

RideMyLeMond

I believe with the Diverge at least; comes down to tire width and also BB height. A 650bx45mm will have the same outer diameter as 700cx28mm and on the Diverge, that may be too wide for the alloy frames and a 6500bx45 on carbon is going to be marginally too small in radius for the BB clearance.

Facanh

700c disc frames will accept a 650b tyre, the question is how wide of a tyre. If you go too narrow a 650b tyre will lower the BB too much since the overall diameter is of course smaller.

So yeah, you can put 20" wheels in your 700c disc frame too, how will they work... That's another question.

Garfield Cat

So what other gravel bikes can accomodate both 700 and 650 and do it well with a wide array of tire widths and bottom bracket height issues? What designer of frames do this?

And more importantly, how is (can) it be done?

Facanh

OPEN U.P. just as an example, they have a bunch of info about the frame on their website.

https://opencycle.com/UP

I'm not a frame builder but I think to simply achieve something like 700x38 and 650x47 compatibility you just need a slightly higher bottom bracket, long-ish chainstays that are dimpled on the inside. And there are options like a dropped chainstay or some companies use pretty much a "plate" so the chainstay is as thin as possible. And of course you can widen the BB but that limits crankset options.





I'm sure there are a bunch of other ways I don't know of.

Garfield Cat

What would a higher bb and longer chainstay do to the ride? Does that mean the overall wheelbase will be longer and therefore a compromise on handling?

Is that what UP did?

Marcus_Ti

UP dropped the chainstay while shaping the seat tube iirc.

Longer stays will make the hike more stable WRT steering...higher BB raises the center of gravity making the bike less stable

Garfield Cat

Then drop the chainstay and allow the chainstay to remain the same size regardless of wheel size. No matter riding on road or gravel, the ride will be more like the road bike. Bottom bracket stays the same, low?

OK, it seems like it took Diverge designers to accomodate and make two types of frames. Whereas the UP is just one design, and that's it.

ksryder

Tried to check your Flickr but it says the album isn't public.

One more post and you can post pictures here though.

Nubie

Just wondering if the OP ever discovered the answer to her/his question. I also recently bought a Diverge (aluminum) and my cousin purchased a carbon version. Hers comes with 38mm stock knobby tires, mine with 30mm smooth ones. I'm looking into knobbier tires so we can do trails together, not sure what width I should get. I read that 38mm was the max my aluminum frame could use, 42mm for carbon. Is this true? I only read this in one review, all the others I've read state that 42mm is the max, making no differentiation between aluminum vs. carbon frames. Can anyone clarify?

Thanks!

RideMyLeMond

Here's a chart that I found somewhere on I believe a Specialized Technical discussion. It does convey that there is a difference on the max size of tire depending on Carbon vs. Alloy. I'm still trying to find the source location of this frame grab.

Nubie

Witterings

Did you try this and if so how did you get on .... I actually spoke to Specialized in the UK yesterday with this exact same query as it's not clear and some of the retailers websites in the UK are saying the Ali ones will take 42's which is really miss-leading.

Nubie

So I never actually tried my cousin's tire on my frame, but I did put 700x35 Panaracer Gravel King SK tires on mine (replacing the stock 700x30 tires). I would say that although the alloy frame probably *could* fit a 38mm tire, it would be an extremely tight fit. Too close for my comfort, anyway. The issue is that the alloy frame has a little "bridge" between the chain stays at the base of the seat tube, thus limiting the tire clearance, whereas the carbon does not. I also feel the distance between the seat stays is slightly narrower on the alloy frame than the carbon frame, though I did not measure. I've tried to post some pics, my frame is the purple-brown one and her's is blue-green (please pardon the gigantic size of the pictures, I could not figure out how to shrink them down):


Alloy Diverge frame with 700x35 Panaracer Gravel King SK tire


Carbon Diverge frame with stock 700x38 Trigger Pro Tire


Alloy Diverge frame with 700x35 Panaracer Gravel King SK tire


Carbon Diverge frame with stock 700x38 Trigger Pro Tire

shoota 

There's a good chance those 35mm GKs are actually closer to 38-40mm depending on your wheels' ID. On my 24ID wheels they measure 39.8mm.