Advice on mtb tyres please

[Darz456]

Hi im planning on doing some cycling camping this summer ( once it stops raining ! ) on a trek hard tail mtb . I have replaced the tyres with some Kenda kwest slick tyres 26x1.5 rated at 65 psi max pressure .
However when i load up the rear rack with 15 kilos the tyre is almost bottoming out . I only weigh 13 stone so i was a bit surprised . I went on a test ride and the tyre did bottom out on the rim a couple of times so i feel this is bad .
My local bike shop says i need wider tyres but i can't see that myself as touring bike tyres arn't anything like 1.5 wide anyhow ?
Do you think i'm ok increasing the pressure past the recommended max of 65 psi ?

Cheers

Darren

 

[albion]

Makes no sense.
They have to be under inflated.

I have 1.5 tyres rated for 55psi to 85psi and they do not even bottom out at 55psi

 

[Peteaud]

I run my 38 wide hybrid tyres at 70 - 80 psi.

1 1/2" is around the same, so try them at 75 ish.

and check your gauge

 

[HovR]

What are you measuring the pressure with. Is there a chance that the gauge is not accurate?

 

[defy-one]

I run my slick shod mtb at 70 psi - something amiss here

 

[derrick]

Check your gauge.

 

[Darz456]

Hi thanks for your replies but i believe the gauge to be accurate as its been used on my other bikes with no problem . The tyre is hard at 65 psi and the bike goes fine with just me on it but when i put on the panniers and my tent ( 15 kilos ) it looks very flat . The bike runs ok with the weight but if i go over the edge of a drop kerb i can feel it bottom on the rim .

 

[defy-one]

What inner tube have you inside the tyre?

 

[Darz456]

Hi defy -one my inner tuber is 26 x 1.5/ 2.10

 

[defy-one]

All i can think is your riding it wrong or the weight is far more than you think????
No offence intended

 

[marzjennings]

I'm almost 16st and I can ride a 1.5" tyre at 65psi with no bottoming out or pinching over rocks.

At 65psi, do a thumb test, how far can you depress the tyre with the end of your thumb. You should only be able to push the tyre in a few mm's.

 

[Crankarm]

Your tyre pressure gauge is most likely faulty. No way your tyre should bottom out at 65psi.

Why are you riding up and down kerbs anyway?

Kenda aren't great tyres anyway. Get some Specialised Armadillo Nimbus (slick) or Schwalbe Marathon Plus Extreme or Mondials or for slicks City Jets.

I have Marathon XRs 26" x 1.6 and x 2.0 tyres. I run them at 80psi which feels a bit hard but even at 65psi they are still pretty hard and wouldn't bottom out.

 

[willem]

Did you check the pressure using a petrol station to inflate the tyre? They often have pretty accurate gear. However, I am also inclined to think your lbs may be right. 65 psi with that load is not that much for a relatively narrow tyre. It is what I use on 26x1.75 tyres, and even those very occasionally bottom out. Other tyres would also give you an opportunity to get something better than the Kenda's. My personal favourites for fast tyres would be the 26x1.75 Panaracer Pasela or the Schwalbe Big Apple 26x2.0. The Pasela would be faster (and is what I use myself), but the Big Apple is sturdier and has more load carrying capacity. I think the 50 mm Big Apple is the perfect allround touring tyre for mtb conversions. It is reliable, comfortable, and surprisingly fast (faster than your Kenda's). Use the Pasela (the version without puncture protection if you want more speed and comfort) or even better the related expensive Compass 26x1.75 if you want something still faster. Use the now discontinued Schwalbe Marathon Extreme for trips with larger off road sections, or the Marathon Mondial for expedition tours. But for anything in between such extremes the Big Apple is perfect, and will solve your problems.
Willem