New tyres or new rims

Robbie_P

Aplogies if this is a really stupid question but here we go...

I have Sun Rims DS2 (622 x 24) on my Cannondale Badboy with Vittoria tyres 28-622 700 x 28 C.

My issue is that the tyres cannot take my weight... 90Kg (with backpack). The tube is pumped to the max but still feels like the tyre is a bit under-inflated. (Presta valves) When riding, if i go over a bump or seam in the road the tyre almost totally flattens and it feels like the rim is hitting the road. Like-wise if i go up a kerb same thing. Even worse, when i'm going at speed, round corners and try putting a bit more power to the pedals it feels like the tyres are about to slip sideways off the rims... it's very disconcerting!

What i really want are wider tyres that can take a bit more abuse and weight... what is the maximum width tyres i can fit on those rims? Or..do i need to actually get wider rims to mount wider tyres on?

Any recommendations for Rims and tyres?

Cheers

desweller

I'm 5kg heavier than you and don't have these problems with 23c tyres... Sounds like they're just under-inflated. What's the reason for not simply putting more air in?

corshamjim

Take a look at the technical information .pdf at http://www.schwalbe.co.uk/downloads/ It should tell you all you need to know about what tyre sizes should fit which rims. You may need to measure the rim width yourself though if you can't find the definitive specs for that rim online. The only one I could find was for the 26" version of the DS2 which seems to indicate it is 17.5mm, so could take any tyre from 28mm to 50mm.

It's probably worth double-checking your tyre pressure with a pressure tester, as the guage on your pump might well be mis-reading. Out of interest, what is the max rated pressure for those tyres?

bails87

What PSI have you got in them?

90kg isn't really that heavy, any tyres and rims should be fine.

Robbie_P

Cheers... I have them at the max psi rating of the try which is 95. The valve physically won't let me put anymore air into them, I've tried.

You say any tire should be fine?! Isn't the width of the tyre dependent on the width of the rim to an extent? Also would it be of any benefit to switch to tubes with a Schrader type valve?

desweller

Presta type valves are good to well over 120psi (the vast majority of road bike tyres use them); rather than the valve, it sounds like your pump is at fault. At a guess I'd say it starts leaking or won't retain the connection to the valve, in which case the rubber gripper that seals to the valve needs to be replaced.

Unless of course you're using a mini-pump, in which case I'm afraid you're always going to struggle to hit high pressures as they just don't shift enough air.

A decent quality pump like the Joe Blow is a good investment BTW.

Having said all that, at that pressure, with 28c tyres and with your stated weight it should still be OK; have you tried someone else's pump to verify that yours is reading pressure OK? It would also be a good overcheck for the connection to the valve.

Robbie_P

Cheers for the input. I have a good quality bontrager charger floor standing hand pump with an auto multi-valve thingy on the end which switches to accommodate both types of valve. The connection is pretty good and secure with no apparent loss of air. I'll try someone else's pump but I don't think that's necessarily the problem.

desweller

OK, can you describe what happens when you reach 95psi?

Robbie_P

When I get to 95 psi/ maybe a bit higher, no more air will go into the tube,the built in tyre pressure gauge hovers around 95-100 and the pump handle will physically no longer go down. With force it will go down but the pressure is too great for the connection and it releases.

Hoopdriver

Have you fully opened the valve?

Robbie_P

Ahaa! What a muppet i've been!... Being the first bike with presta style valves i wasn't aware that you had to unscrew the valve before attaching the pump. I hadn't even noticed that it could do that. All sorted now. Tyres rock hard. Thank you!

Noticed while i was doing it though, i've got a bit of a bald patch starting to appear on the rear tyre. Any tyre recommendations?

I noticed that on the new Cannondale Badboy's they come with the Schwalbe Kojak tyres but also on different rims so i don't think they'd fit mine. They are also slicks I noticed. Logic seems to tell me that slicks would not be good in the wet and also more suspectible to punctures... but am i wrong? On the Scwalbe website i get the impression that they do actually have pretty good traction.

http://www.schwalbetires.com/bike_tires ... ires/kojak

Hoopdriver

Glad that's sorted.

There's lots of possibilities for tyres depending on what you want to do with your bike. On my expedition tourer/winter bike I use Schwalbe Marathon Plus. They are rather heavy, but the are almost bombproof as far as punctures go. In fact I've never had a puncture with these tyres. They also last forever - 20,000 miles oor so. They roll surprisingly wll and I have ridden man a century ride on hem

On my Pegoretti road bike I use Continental 4 seasons GP. Nice responsive tyre with good puncture resistence and they wear reasonably well too. Nice tyres.

On my lightweight Enigma tourer I have Panaracer Paselas. Good light touring tyre that wears well and seldom gets punctures.

I don't race so I know very little about the faster sportier tyres, at least not from personal experience.

I hope this helps.

bails87

Yep, unscrew the valve, then push it down quickly to make sure it's open.

As for tyres, anything in a similar size will be fine. The actual make/model of tyre is a personal choice. Continental Gatorskins are good for puncture resistance but I found them a bit slippy in the wet, so now I've switched to 700x25 Conti GP 4seasons which seem better, they've been 'reliable' so far too.

Assuming everything else is the same, slick tyres will grip the road better than nobbly ones because there's more rubber on the road, so more grip. This is true whether it's wet or dry. Car tyres have tread to stop aquaplaning. A bike tyre is too narrow, and moves too slowly, to aquaplane, so the grippiest tyre on a 'solid' surface is a slick one. Off road, where nobbles can dig into the ground, is obviously different.

Robbie_P

Thanks for the input guys... will check out the Marathons and the Conti GP's