Over the weekend I built my new bike, a Orange Clockwork
I fitted a Chunky Monkey up front, and a Smorgasbord at the back..

there is very little room at the back by the chainstays only a few MM..
I didnt even anticipate this might be an issue before ordering the tyres as would have thought a british designed frame would have masses of room.

so if it fits even just, is that good enough, or should i worry about eating through the stays with my mega rad knar, hard turning skills!?

if I should worry and need a smaller tyre, whats going to come up a bit smaller, but still be tough? (sorry turned into a what tyre thread!)

I wouldn’t worry about the frame, but you might find it rubs when climbing or in the little ring, and mud will be a problem…

If its only a couple of mm, it will probably rub. Dont think the tyre will wear through first either!!!

The inside of the chainstays on my Cove Stiffee are down to the metal in places from running a 2.5 Conti Der Kaiser.

It depends on the frame too, some need more room than others- flexible frames frinstance will use up their clearance just with the bend.

Losing a little bit of paint to tyre or mud rub doesn’t bother me, but if I can feel or hear the rub I reckon it’s too much.

If its only a couple of mm, it will probably rub. Dont think the tyre will wear through first either!!!

It’s rubber, it will wear down and stop rubbing!

That was exactly my thought process shortly before I wore a 1mm deep groove into the chainstays of my first aluminium MTB.

On the test ride (a quick lap round sherwood pines) there was a couple of occasions I heard some “rubbing” when on the pedals out of the saddle, and think it must have been the rear tyre catching. It was late and dark once I got back, so yet to closely examine the frame, but suspect I may be better off finding something a little smaller

Had the same issue when I built my clockwork. Started out by fitting Mountain King IIs, and wasnt happy with the clearance (think they were 2.4s), so sent them back and ended up with Maxxis Ardent’s (2.25’s) which are spot on. Big enough volume but never had any issues with frame rub.

Both are 2.25 made by maxxis I thought that they would be the same size?
Incidentally run an ardent exo on my fs and thought the smorgasbord would be a cheaper similar option

Will have to put them side by side to see if the ardent comes up smaller, although different rims and different wheel sizes might blow that out of the water

Sometimes things will get caught in the tread pattern and strike the frame (seatstay usually). Watch out for that before suspecting other components.

I would run a rear with tight clearance especially on a hardtail, but think twice about the front. Some tyre/rim/fork combos seem to have more interference under fork compression.

fitnessischeating – Member

Both are 2.25 made by maxxis I thought that they would be the same size?[quote]

From the company that brought us the 2.7 that measures 2.5 and the 2.5 that measures 2.35, and the 2.35 that’s smaller than the 2.25, and the 2.35 that’s almost exactly the same size as the 2.5? Maxxis are good at rubber but they should have realised it’s not the right material for a ruler.

FWIW CST also make Specialized tyres which are generally pretty accurately sized- the decision of whether to put a true or false tyre size on the side seems to be the client’s not CSTs.

there is very little room at the back by the chainstays only a few MM

There’s a good finger gap between a 2.25 and the metalwork on my bikes and yet there is still evidence of frame rub.

Not so much the tyres but things that get stuck in the tyres. Hard things like pebbles, grit, snow ice etc

Just saying like.

Both are 2.25 made by maxxis I thought that they would be the same size?

Err…no 🙂

fitnessischeating – Member

Both are 2.25 made by maxxis I thought that they would be the same size?

Sorry, not sure what you mean? MTN king II are available in 2.2, but I initially tried the 2.4s, before fitting the 2.25 Ardents.

The smorgasbord I have fitted currently is described as 2.25, as is the ardent, wasn’t referring to your conti 2.4

I see!

Smorgasboards are massive, when I stuck mine in the frame I was surprised how little clearance it left when compared to the 2.35 high roller it replaced.

That was exactly my thought process shortly before I wore a 1mm deep groove into the chainstays of my first aluminium MTB.

Aye been there done that.

You want a “good bit” of clearance. I reckon 5mm is about minimum

Tyre sizing is a total ballache. Can you imagine if every other component was sized the same way?

rubbin’ son, is racin’

So the 2.25 ardent and the 2.25 smorgasbord are pretty much identical in size, albeit different rims.

I made the same mistake about 20 years ago, I was so tight I went round with a scalpel cutting tread off the edge of the tyre, it worked.

I like it…
Might be the way to go, and keep a large volume tyre out back to ward off rocks!
Either that or I’ll retire it to front only duty…
Any opinions on the spesh ground control 2.1?

Yep nearly sawed through my Heckler swing arm due to a bent hanger and out of true wheel.

You can stick some tape on the inside of the stay. If you wear through the tape get a new tyre. I have a clear finger gap on my Intense and can still mark the stays so something must be pretty flexy back there