TimJ

Most races here in socal are mostly on grass. I hate grass. I hate it so much. It feels like I'm pedaling through molasses.

What can be done to be faster through grass, tire-wise? More pressure? Skinnier rather than fatter tires? Low-profile knobby, file tread?

Anyone have any ideas?

I'm currently running a 35c maxxis raze in back and a 35c ritchey speedmax in front. This combo is good for dirt because I need something that really grips in corners in front, but on grass it feels like maybe the speedmax is real slow, but it's hard to tell if that's really the case or not.

SpongeDad

I run Michelin Mud2 on grass and (duh) mud which are 30mm IIRC. Michelin makes a smoother tire, the Jet, but that's not knobby enough for off camber, wet grass handling for me.

Grass is slow, mud is slower; practice lower cadence drills

TimJ

The grass here is dry. I've been googling around and a dude at velonews says for dry, bumpy grass like he often races in CO, he likes a file tread. Dry, bumpy grass is what we have, but then elsewhere I see people saying "dot" pattern for grass, file for mud.

Arg.

flargle

Fat tire, low pressure. Ideally tubulars.

Two things make grass slow. The first is the grass itself, which you can't do too much about, except try to find the lines where it's been flattened down (although the consensus line is often the wrong line, don't follow it slavishly). The second thing is the bumpy surface underneath the grass. A fat tire at low pressure conforms to the surface better than a skinny tire at high pressure, which in turn leads to lower rolling resistance.

I haven't seen any numbers on file tread vs normal tread, but I'd be surprised if it makes very much difference in terms of rolling resistance. Normal cross tread is already pretty low. Much more important is the volume and aire pressure of the tires.

Biopacer

If athletes who play on grass use cleats... maybe you can stud some thick walled clinchers? 2 very sparse rows on the back tire might help grip and 'gnash through the grass, unless studs violate CX rules.

TimJ

I've read hints of stuff along these lines elsewhere. It's kind of the opposite of what I've been doing, I've got fat tires but I've been thinking high pressure for some reason.

flargle

With high pressures you waste all your energy just bouncing all over the place. You want your power resulting in forward motion, not vertical motion.

Andy_K 

I ran high pressure in my first race (last year) and I couldn't believe how slow I was on grass. I'm still slow on grass, but now at least proportionally so to everyone else.

BTW, don't underestimate how low you can take your tire pressure. I use 700x35 Maxxis Locust CX (clinchers). The sidewall lists 50 PSI as the minimum tire pressure. I ran them at 33 PSI today. I weigh 185 pounds. I'm a bit perplexed by this, but it's working for me. I'm sure the width of the tires helps. It was a flat course, but it had some bumpy sections that I was hitting hard enough that my saddle clamp broke loose. I'm starting to think pinch flats are an urban legend.

Obviously, I'm not saying that you won't pinch flat at 33 PSI, because there are obviously a lot of variables involved. What I am saying is that you should keep lowering your pressure until you find the place where you start having trouble. I'm still lowering.

UBUvelo

do cx courses ever feature mulch/bark sections? THAT'S tough, esp. when wet

benda18

it sure would suck to find out, right?

Andy_K 

You mean like this?



This is the course I raced today, but the picture is from last year. This year, there were only a couple of flat patches 10-20 yards long. Even with that, I saw a guy fall over sideways today. I'm guessing he just wasn't going fast enough. Usually you only see that in sand.

TimJ

I used to run about 35psi but I've been trying higher pressures this year because I couldn't tell if the lower pressure meant slower or faster. I'll go back to low pressure. Thankfully next race doesn't have any grass.

erichkopp

I'm running 700x35 Kenda Kross Supreme tires with a min. pressure of 50 PSI and pinch flatted at 45 PSI yesterday. I only weigh 130 lbs, but maybe it was a fluke. I also plowed into a good sized root in the middle of a bunch of others, but I was still surprised.

Andy_K 

Yeah, it would, but it would also suck to always be running my tires at higher pressure than I could. Honestly, at 33 I'm starting to get nervous about the project.

ridethatbike

just make sure you put some baby powder in with your tubes (for you clincher types). Supposedly helps with pinch flats. At the very least, it smells nice.

Andy_K 

I do that. Maybe it's working. I've heard it's a myth.

Brian Ratliff

Tubulars at 25psi. You can get an aluminum tubular wheelset for fairly cheap. Tubular tires are invaluable in cross.

TimJ

New wheels are out of the question. So is $100 a tire. I was laid off not too long ago so swinging a new set of tires is barely a possibility.

nitropowered

Buy them used. I'm selling a set of tubs for $100/pair. New but have been glued. Tubulars are the single best upgrade you can make in cross

flargle

Just run clinchers at lower PSI. Practice enough to figure out how low you can go. Local mtb trails are great for finding out.

TimJ

That should be a great deal for someone with a budget of more than $50 or so.

hocker

I agree. I picked up a set of Easton 70x's and some Fango's and it really has made a world of difference. I'm just a beginner so I was a little reluctant to spend the $$.

stevage

>I'm starting to think pinch flats are an urban legend.

Heh. I've had two. One on a 23mm road tyre at over 100psi (hit a minuscule kerb just a little too hard). The other was a 40-something mm knobby mtb tyre - forgot to pump up the tyres after I got the bike off the web. Must have been something like 10-15 psi

Both times I had to wonder why rims can't be made gentler on tubes - why should they be so sharp?