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I think I'm going to give a trials tire a try in the spring. I have a spare wheel I intend to set up for the trial tire and have one for a knobby.

From what I gather trials tires like to go slow and grip anything. So would a larger rear sprocket be the way to go? I need one for the rim anyway.

Now I am running a 12/47 setup and it works well for most of what I do.

I would try it out first with your current gearing. You can always make the swap afterwards.

Not a bad Idea...I noticed a little torque loss the first time I switched to a T-Tire but my gearing was 13-48...

I need to buy a new sprocket for the rim I am going to use for the trial tire and didn't want to buy too many. And I'm looking for a quick swap from one to another so swapping sprockets isn't really in the plan. Right now I have a 45, 47, and a 48.

It's all about tire sizing.

You say the trials tire is designed for "slow and grab" and if that what you really want to do "slow for the grab" then I would go with the largest diameter rear cog on the market for the KDX.

Might need a longer chain, but that's easy too since there's a master link.

If the T-tire is taller, then down gearing may be needed, if the tire is shorter, then you will gain torque.

Knobs can be figured into the tire height depending on the type surface it will be used on.

Be careful. When I went to a 12t front sprocket with my trials tire I found myself flat on my back more than once. Too hard to keep the front down with all that grip and a little extra torque. Going back to a 13t helped :).

Try it with your current gearing first. And don't be afraid to ride it hard and fast, either. There's nothing about a trials tire that says you need to ride more slowly.

The slow and grab was referring to not spinning to get traction like a knobby but let the tire bite in.

I try the spare 48 that I have and see where that gets me. Thanks

Yep. Hope it works out for ya!

I ended up getting a Michelin trial tire. The 48 sprocket I had turned out to be worse than I had originally thought so I bought a new one.

I have been reading about people running as low as 6 psi in the trials tires. Do they stay on the bead that low? How well does the rim hold up?

I'll probably give it a try tomorrow if it's not too muddy. And probably with a little more pressure to start.

To find equal gearing to what you have now, the formula would be:
present
gear ratio x tire circumference = distance

12/47 X (old tire cir.) = distance
Then:

12/? X (new tire cir.) =distance

12/? = distance/ new tire cir. Then:

12/(distance/new cir.)=rear sprocket.

I'm guessing you'll only need to add 1 tooth.

rbates9 wrote:I ended up getting a Michelin trial tire. The 48 sprocket I had turned out to be worse than I had originally thought so I bought a new one.

I have been reading about people running as low as 6 psi in the trials tires. Do they stay on the bead that low? How well does the rim hold up?

I'll probably give it a try tomorrow if it's not too muddy. And probably with a little more pressure to start.

6 psi works, even 2 psi works. But for how many time?

I run 11-12psi with a HD tube and I don't bother with flats,dents ect... and I think I ride the same speed vs a knobby.

Michelin have softer side walls, your idea is not bad. Start with a higher pressure and adjust.

I've found with the MT43, if I run into a particularly nasty section, I can air it down to about 4 psi and tractor over anything. When riding faster, at lesat 6 psi is needed to prevent pinch flats. Carry a good gauge and some sort of pocket pump and play around with different pressures.

Thanks for the advise. I was going to give it a go today but when I went in the back woods at my house with the old knobby I found that it was about 2-3" of snot on top of frost so I decided to waite until the ground is a little firmer. I don't want to be disappointed in the tire because I was trying it when it should not be run.

I bought a Bridgestone ultra heavy duty tub to put in the tire and I think the tube is thicker than the sidewall of the tire!

The weather is supposed to be great this week so I might get to try it next weekend on some real trails.

I gave the trials tire a go tonight and I must say I am surprised! The ground is a little soft still but I was able to go everywhere I went with the knobby. (8psi)

The trials tire does seem to spin a bit more in the fresh forest loam but I was expecting that. I was however able to pull the front end up just about any where I wanted to. And just because it was spinning didn't mean I had stoped

I went with the 12/48 gearing and I am thinking that I may have wanted to go up a little more with the rear. The trials tire is a fare amount taller making the gearing a little taller but I will try what I have on some rockier trails before I make any changes.

So far I like it! Not convinced it will be the only tire I run yet but it is nice to have a spare rim so I can go back and forth.

Did you rode aggressive or just lurking around?

I only played with it in the back woods. A little bit of both, just seeing what it had to offer.

Yesterday I went for a ride with four other people all running knobbys and had no problem making it where they went. I did however find the trials tire is not happy on loose ground at speed. A few times I tried to lift the front wheel to clear an obstacle only to have the wheel spin and the bike plow into the ditch or tree. The cornering is not good and when the bike comes on pipe it gets much worse. But when the trail got rocky I found traction on all the wet rocks that a knobby would have spun on. There was spots of snow and ice still on some of the trails and the trials tire did do very well there.

I ended up putting the knobby back on towards the end of the day.

With the trials tire I went from about 15 psi down to 11 psi a little at a time to see what the sweet spot was going to be. I'm not sure if I found it.

So far I would say,

Good:
hard wet ground it is great.
can go anywhere.

Bad:
scary at speed.
not happy on loose ground


With my first hand experience I think leaving the trials tire in the barn for another month until the trails dry up some is the best bet. I am happy with it over all, just I think that I was trying it a little to soon on too fast of trails.

i replaced my knobby with a trail tire (mainly because i use my bike more as a commuter bike and 90% of my driving is on actual roads)

the only downside ive found on the trail compared to the knobby would be loose mud
(if you've ever made it across a soggy cornfield you know what i mean)

i have found the trail tire lifts the front end on hard packed sand and pavement where the knobby would not

A good hard pack - medium terrain knobby will hook up nicely on packed pavement - and is probably more versatile than the trials tire, especially if you ride where the terrain varies a lot. It just takes a while to find a really good compound and design of tire that works well for the widest applications for where you ride - and is reasonably durable.

Like everyone I'm always on the quest for the best ________ you can get.

I had heard a lot of great things about the trials tire so I figured why not give it a try.

The place I rode yesterday is typically pretty dry hard pack with a lot of rock and very little mud. Yesterday was much looser than normal.

My reports are just my opinion of the trials tire for how I ride and where I ride, by no means am I trying to pick a fight with anyone or discredit other peoples opinion.

Any suggestions to get the most out of it are welcome.