Skating on a trail and other problems

Acdc

Dont worry its not as mad as the title sounds!

I have been mtb riding for about 10 months now and have never experienced the tyres skating on the rocks at my local trail centre as much as they did yesterday yet the trail conditions were as normal...

I was wondering if it was the tyre pressure? I rode the coast to coast at the weekend so my tyres were up really high. (At about 35 - 40 PSI) is that too high for trail riding? Or is it a bad riding style, bad tyres or too much (or too little :shock: ) speed? I doubt it was too little speed as i wasnt hanging around out there! The 'skatiness' is hard to describe other than the tyre skipping and slipping off the rocks...

If you are wondering my bike is a 2010 Cannondale Trail SL3 (with flat V8 style pedals - thats the only none stock bit except the trip computer) - so the tyres are a pair of Hutchinson Iguanas... The knobby bits on these tyres had, when new, grooves cut in the tops of the knobs, however these grooves have now worn out... Time for new tyres? The knobby bits are still there, but they just didnt seem to grip the rocks - especially when damp from puddles...

My other problem is the disc brakes.. The front brake was, until a few days before C2C ride nice and stiff and responsive, yet it now is really loose and soft and needs to pulled on almost entirely before the pads grip sufficient to slow the bike. Which means i was putting a lot of work on the rear brake - which thankfuly is still as good as new - but that was NOT helping with traction problem mentioned above. To make the problem of the front brake worse, the 'weight' in the brakes or if you like the pressure in the hose seems to come and go at almost random...

Does the front brake need bleeding and if so how / point me to a guide please

Thanks for reading this far and any help would appreciated!!

97th choice

Too much rear braking. Sounds like you need new pads at least, possibly a bleed.

Acdc

Yep could be to much Rear brake but it was, half the time at any rate, the front wheel that went slidey...

ddraver

Brake needs bleeding

45psi is high, that's sacrificing grip for rolling speed for sure, sounds like the tyres may be a bit worn but they won't have changed overnight. On the other hand a greasy rock is a greasy rock and nothing will stop types slipping, just have to get used to the feeling....[/list]

Acdc

Ill let the tyres down a touch before i go out again then, thanks guys!

Ive just checked the workshop section on here and noticed the article on brake bleeding so ill have a read of that.

paul.skibum

35psi is a decent tyre pressure - our rental fleet are set to 35-40psi for the DH runs on our mountain.

The pressure in the brake levers fading in and out will need a bleed - I'd suggest there is also a chance you have glazed your pads as that will effect the feel fromt he brakes and lead to lock up and loss of control.

Probably some skill issues in there too!

timpop

@paul.skibum. Okanagan eh, nice wine and the ogopogo.

Have you checked how much pad is left too? It's hard to comment on your tires without seeing them but sometimes rocks a just slippery. Although your wheel angle and body position can make a big difference on the day especially if you're a bit tired. Who knows...

captainfly

Was there much road riding on the C2C ride? There may be a contamination issue with the tyres and brake pads, spiied diesel can be a fooker, I'd clean and degrease my tyres as 35psi front 40psi rear shouldn't cause much problem unless you weigh under 150lbs. aso give your brake pads (take them out and check there is material left) and disks a good clean with isopropanol, then give them a bleed (or take them to your LBS and pay them to do it).

Acdc

Yea the c2c was mostly road based... Im going to the LBS workshop tomorrow so ill have a word with the guys there bout new pads and i think that captainfly is onto something with the contamination thing as the rocks at the trail arent normally as slippery as they were especially considering they were dry.... To give an idea of how slippery they were.. Ive ridden faster on that trail with less slipping in the rain than i did the other day in the dry :shock:

Anonymous

The knobs on tires don;t grip rocks, the rubber does. The knobs are there to help them cut through the dirt to either lock themselves into the ground, or if possible to get to the rock underneath.

Some tyres grip better than other, in differing conditions. Another thing that can change grip is the dryness of the trail.
Perfectly dry trails don't have much grip, a little bit of moisture helps bind the ground together, giving the tyre something to bite into.

felix.london

indeed Yeehaa

I had first hand experience of this yesterday. As posted earlier in the week, I've been having real trouble with my Specialized Resolutions on dry, loose, stony trails.

There was just a tiny bit of rain yesterday which didn't even get through the trees to the trail but just the moisture in the air was enough for me to be taking corners a lot quicker than I have been able to.

Btw my Resolutions are rated 35-80psi (!) - so 35-40psi on these tyres wouldn't be high at all. These tyres are notoriously bad in dry conditions. I have some replacements on the way 8)

getonyourbike

I haven't found a problem with running tyres below that rated pressure. I'm running my Maxxis Advantage and Minion DHF at 30PSI when they're recommended at 35-60PSI. I am pretty light though

Acdc

Hmm thanks again! I was out riding again a couple of days ago and the slippery feel had gone, yet the conditions were the same so i reckon it may well have been road grease on the tyres... FYI the Hutchinson Iguanas are rated at 20 PSI to 50 PSI which seems very low compared to everyone elses tyre pressure ratings... Do any of you agree with that?

Also the bike is booked in at the LBS workshop for a brake bleed so that should sort my problems - hopefully.