DVD23

Hi everyone.
New to this forum and after some advice.

I recently purchased a Van Nicholas Blaze which came with Reynolds carbon assault wheelset tubeless ready.

After reading the data specification on the frame its states that it can take a 700x23c max on the rear as to accommodate the cut out on the seat tube. Unfortunately with this size tyre it still rubs... Am I missing something or is it to do with rim width?

Don't really want to keep riding on 20c tyres as they are hard to come by and really don't suit the riding I'm planning to do.

Any help would be greatly appreciated.

ThanksDan

Oh and if you have any gp4000 700x20c DM me I'll buy them for the meantime 🤣

Bill Kapaun

Try a different brand 23mm until you find one that fits.

Iride01 

Were the specs you read specifically for that year model frame? If not, then there is your answer.

Nothing will change what it is unless you want to modify the frame and that's going to be big bucks.

Perhaps maybe a tubular tire might be a slightly smaller circumference in the same size width if there is such a thing for tubulars. But I only know how to spell tubular and have never used them.

Just more guessing but on those drop outs is it intended for the axle to bottom out in the slot or should the QR be clinched lower where the tire might not rub... albeit will still be tight. disregard. I just saw the pic that shows the better view of the dropout.

And, are you certain the frame wasn't intended for 650's?

Andrew R Stewart 

The label "700Cx23" is just a general reference and not a specific dimension. Real tire dimensions depend on rim width and how the company decides to measure their tires. There are many examples of labeled "sizes" drifting both larger and smaller than that label number would suggest.

Too bad you bought a bike with such a limited ability to run tires with greater functions than what came stock. Andy

DVD23

I'll give that a go thanks 👍

DVD23

Thank you for your help. Regarding the skewers that's not a bad shout I'll look further into this.

Definitely intended for 700c

Cheers

DVD23

Yeah I get you mate shop I visited had a similar outcome I'll try a narrower rim width you never know.

Does suck about the limitations but bike is so nice to ride. Might just have to grin and bare the 20c until I find another resolve.

Cheers

Crankycrank

I can't tell from the photos but it looks like it's rubbing more at the top of the seat tube dimple than the bottom. Try clamping the QR a little lower in the dropout to move the wheel lower a couple mm. If it works you could make a semi-permanent spacer to stay on the dropout or axle.

sweeks

That's a pretty bike, but I'm having a hard time imagining that any wider tire that fits that rim will clear the seat tube. The bike may have been designed for 700c wheels, but *could* the rear be 650?
Trivia: Van Nicholas started out as "Airborne" and morphed through "Flyte" on the way to its present state.

tFUnK

Oof, rough. Besides the good suggestions already presented, you can try the old trick of adding some "shims" to the top surface of the rear dropouts such that when the wheel is installed, the shims push the axle lower. I think there's a commonly used term for this but I hope I've articulate a clear enough explanation.

DVD23

Thank you for all your help/input I'll take all these suggestions and see what I can do. I'll post up any progress incase someone in the future needs similar advice 👍

Litespud

If you bought the bike recently, can you return it? Close tire clearances are one thing, but that’s ridiculous. If I received that frame, my conclusion would be “You made the chain stays too short - send me another”

DVD23

It was made in 2012/14 mate, I bought it second hand but in the process of checking everything i.e frame for cracks dents etc I overlooked the tyre size 20c 🤦

tFUnK

Contis (at least the 4000s) run wider so perhaps another 23mm tire can clear it. Schwalbe Ultremos (or the current equivalent) might work.

Crankycrank

There is also this site which will give measured tire heights of the tire mounted and inflated. Road Bike Tires Test Results | Bicycle Rolling Resistance You may have to pay a small fee to get the info you need. They used to offer this for free but It's a lot of work to get all this info together so fair enough. Anyways, buried in all the info will have the "Measured Height" listed. Probably won't be exactly the same for rims that are different width than yours but you can compare the differences of yours to other tires to find out as they use the same rims for all measurements. Anything with a 2mm+ lower Height would probably work. Also if they don't list specs for 23's just compare the 25mm width of yours with other brand's 25's to get an idea. Also pay attention to whether you're looking at the Tubeless or tubed versions listed.

icemilkcoffee 

That's where I'd go. 650b conversion.

DVD23

Amazing thanks mate I'll check it out, as you says it's surprising the difference between brands 👍

DVD23

I'll also look at 650b could be an option thanks 😊

Andrew R Stewart 

I have not researched 650B tire selections in the narrower ranges lately, When i last looked into the sub 35mm wise options I had not found much, if any actually available. It seems to me that the reason to swap to 650B is to significantly change the nature of the bike's ride. The usually much wider tires (from common 25/28s to 38+) is much heavier, typically runs half+- the air pressure and often mounted on a heavier and wider rim. The bike's feel slows down (note I said feel, not a timed measurement), the minor road vibrations smoothen out and the big ones loose some of their "height" and the steering loses some quickness what with a larger contact patch (with its more rounded shape) and greater rotating mass. I'll also add that caliper brakes lose some leverage (what many call power) due to the pads being close to 19mm further away from the frame mounts.

So in my view the reason to change to 650B wheels is not to gain tire clearance but to gain tire width. This is fine if you want a slower feeling bike that is more stable on the less ideal surfaces. I'm not sure if the OP has this goal in mind.

Horses for courses. This 650B swap thing to me is like taking a sports car and lifting the ride height just so you can run wheels/tires with greater aspect ratios. Can it be done, yes. Will the car feel like a sports car still? Not really. Or taking a 4 wheel drive pick up (made to handle a plow blade) and putting low aspect ratio tires on it so it drives more car like. In both cases I would offer that the vehicle is the wrong one for the new need.

Of course, I see full suspension MtBs with 1.25 tires on them at some club rides Andy

DVD23

Yeah I agree. To be fair the bike itself is built for speed and as you say I do t think 650b option will fit the character of the bike. Another member of this group has kindly said he'd sell me a pair of gp4000 20c for the time being. At least that can match the gp5000 23c I'm running upfront. Staggered setup I know but better than nothing. Be good to get some decent 100 milers in the tank and see how harsh the ride is with 20c. Tha KS for your insight/help.

Cheers

Mackers

Correct me if I'm wrong but that looks suspiciously like a TT frame.

DVD23

Yes it is a TT frame mate 👍

70sSanO

As for a 650b conversion, Continental makes a GP5000 in 25mm and 28mm.

The main issue would be a lower BB if you swapped out front and rear, which you want to do to keep any semblance to your current geometry.

A theoretical 20-700 has a diameter of 662mm. A 28-650 is 640mm. Basically 11mm lower. There might be a pedal strike concern.

I have no idea on the impact to bike performance. Much has been written on the subject that seems to indicate performance improves with width, up to a point I imagine.

John

Edit added: Having ridden 700x20 years ago and now riding 700x25 and 700x28, (on the same bikes), I haven’t noticed a significant difference with the higher BB effect. It is smaller at 5/6mm and 8mm, but the bikes seem to handle as well.