I inflated my ksf250 tires to the manuals recommended psi.....right around 4-4.5. They're the factory original tires, the rounded type, with plenty meat left. Took it out for the 1st time in the trails. The ride was plush,...but it under steers really bad. Also on a hard corner it seems like the rear tires want to fold over,..especially if I'm on the road.

I'm new to atv so maybe this is normal? I understand if I increase psi I'll lose some ride quality in the bumps.

Do the squared tires have a stiffer side wall?
Maybe because my tires are old the sidewall has weakened?

Your thoughts are appreciated.

 

Hold the bars straight,get off and look at the front tires. Some manufacturers want them toed in a little, some like Polaris toed out a tad(1/8-1/4") See if you can check for your model and you can use the old string mode for checking or use an aluminum stud like we did in the shop. One person held the bars straight and tight,another tightened or loosen the tied rod shaft to align the front tire to the rear and allow for toe in or out.Plus the pic is one guys method of doing this.Plus on the tires look at the side wall as it usually shows recommended pressure or max pressure. On most of our full size machines we had 5 psi .

 

Only shows max psi. These are factory tires so I'm going by the manual. Will play with psi. I'm 230lbs so that could be considered a "heavy load".

Will check for toe in. Thanks.

 

I normally run 7 psi in the front and 5 in the rears. I've found if the fronts are too soft, they tend to roll under a bit in hard corners.Play around with the alignment, every bike handles a bit differently. I like to put someone of my size on the seat to check. Try some toe in, neutral and some toe out. See what suits your style of riding.

 

I assume you have an accurate gage for reading pressures that low. A zero to 15 psi pressure gage would be appropriate. ATV owners need a good low pressure gage to check tire pressures. The difference between 4 psi and 5 psi is 20%. A pound makes a difference.

David

 

I run mine a little higher than recommended. Around 5#. The recommended 4# will give best traction, another lb. or two will give you better handling, at the expense of slightly harder ride. Adding extra air will also save your grass some if it is ridden a lot around the yard.

 

I have the 0-15 tire gauge that came with the quad. Whether its good or not,...I don't know. Just seems I need a bit more air.

Thanks all!

 

I guess I'm the oddball.

I like 3 psi in the front and 2.5 psi in the rear and I'm running radials.

A lot of ATVs feel like they "push" in corners. My BF does more than my Rubicon did. Same tires same psi.

Too much TP and you lose all of the advantages that radial tires have over bias ply tires.

 

The BF has a lot more power than the Rubicon had. Given they have close to the same size tires, having about 75% more power will probably make it push a bit more. A bit more weight too and higher center of gravity with the irs as opposed to the solid rear axle of the Rubicon. Not to mention much more suspension travel as well.
I'm just afraid to go too low on TP. It just looks strange to me if the TP is so low you can actually see the sidewall flex. I think that would be great for very slow, technical trails but too low for higher speed riding. Around 4 psi would seem to be a nice compromise for slow speed traction and high speed stability.

 

I'm not a racer but I ride pretty hard at time and never had an issue with the lower tire pressure. These pressure just seem to work better for me.

If you run too much TP the sidewalls wont be allowed to work like a radial tire is supposed to work by letting the tire "roll" to keep all the tread on the ground.

I haven't ridden everything but I've ridden tons of different ATVs and my BF tends to push more in corners than most.

My BF is definitely a different beast than my Rubicon. That's for sure.