ByronK271

Hi all!

I absolutely need to change the tyres of my old MTB because they rebound like crazy even at low pressures (35 psi). Do you think a Conti Race King 2.2 can fit in the back? The front derailleur looks like it might rub on the tyre when the front gear is set to 1 (the smallest sprocket).

The current tyres are 26 x 2.0 (52x559).

dsbrantjr

I don't understand what "rebound like crazy" means. Isn't that kind of what pneumatic tires do?

Understand that tire sizes are not well standardized; the 2.2 inch tire may be larger or smaller than you think, compared to what you have.

Also consider that too little chain stay clearance will mean that the tire could rub them if you lose a spoke, which might make the bike unrideable and result in a long walk home.

cobba

It'd be easier to read the measurement on the tape if it was on top of the chain.
The Race King 26 x 2.2 (59x559) should be 7mm wider in total or 3.5mm wider on each side.

The chain and derailleur look like they'll clear the bigger sized tyre but there won't be as much clearance as there currently is.

How much clearance is there with the chain stays and seat stays ?

Tell us more about your 'rebound' problem.

ByronK271

What I mean when I say the tyres rebound like crazy is that when I go over small bumps on the road the vibrations are unbearable which makes the bike practically unrideable. Couldn't that be solved by switching tyres? The Conti Race Kings are very big for their nominal size from what I've read.

ByronK271

Clearance between the chain stays and the tyre (measuring from the side knob) is 12mm. Clearance between the seat stays and the tyre is 8mm. Clearance between the front derailleur and the tyre is 3mm.

cobba

Looks like the 2.2" tyre is a no go.

What sort of seat do you have, maybe a seat with more cushioning would make your rides more pleasant.

well biked

Whoever said that has apparently never seen one in person. Conti's mountain bike tires are notoriously narrower than their stated width. Of all the major brand mtb tires, they're my least favorite, FWIW.

As for the question: "will they fit?" The only way to know is try. I kind of doubt it, but there's no way to know for sure without trying it. They might, they might not.

ByronK271

Is there any way I can adjust the front derailleur so as to increase the clearance?

I get up from the seat when going over bumps so the seat is not the problem. I went over a few yards of cobbled pavement last Saturday and I had to stop because of the intensity of the vibrations. The back of my neck still hurts 6 days later.

rhenning

Lower the air pressure in your tires. They dd not have to be the number on the sidewall which is maximum. Dial the pressure in for your body weight. Roger

ByronK271

I need to lower the pressure below 30 psi (that's less than the recommended for my weight) to get a somewhat comfortable ride. This has the unfortunate side-effect of making the tyres feel squirmy. I suspect something is wrong with my tyres. It just can't be normal for a bike to feel like a rock drill when going over cobbled pavement, even if I was running the tyres at their rated max of 40 psi.

I think I'll try a cheap pair of tyres of the same size and see if it solves my problem.

FastJake

Unless your tires are extremely thick or solid, the whole "rebounding" thing is a simple issue of pressure. I run my mountain bike tires at 20-25psi but those are fat 26x2.35s.

At a reasonable pressure most MTB tires WILL squirm on pavement, they are not designed for it. If you only ride on pavement get some 2.0" slicks. If you go offroad as well get some tires with a less aggressive tread.

Question: are the tires in your photo Kendas? I have a few of those, or something with a very similar tread. In my experience they are actually the best combination of decent offroad capability and good road manners. I think I used to run them around 25psi.

ByronK271

They are made by Rubena. I tried them at 20 psi once and got a pinch flat. According to this calculator I should be running the front at 38 and the rear at 41 psi.

wesmamyke

You seem determined to run larger tires so I would point you here: https://mtbtires.com/specs/index.html

Real world measurements of many tires, the race king tires don't seem to be listed but it should give you an idea of what to expect from claimed tire sizes. FWIW I never run mountain bike tires inflated more than 30psi even on the road.

anixi

Old MTBs usually don't allow for that wide a tyre/tire. I would suggest the same thing in a 1.95" tyre/tire.