I have been planning on getting a 5.10" tire to replace my stock rear tire. My main reason for going fatter is to improve onroad traction and resistance to sinking too deep in mud. For the same reasons I have been planning on going to a 3" front tire.

I was discussing this with the owner of my local shop (independent shop, not dealership). This guy really knows his stuff, so I put a lot of faith in his opinion. He recommends that I don't go any bigger than 120mm (4.6") on the rear. Now that I think of it, I don't recall exactly why he is against the bigger size, but he definitely cautioned against it.

My question is, what is the good and bad with going fatter on tires. I know to expect a modest decrease in overall power because the bike is having to work against a larger contact patch, but I am okay with that. Am I missing something? I do not see any real downside to having larger tires.

Thanks,
Chris

 

When I ordered my Kenda I think its a 18 X 5.10 well hang on I'll go check in the shop. I said hang on like I was in a chat window .....that's sad I know. Yep the front is a 3.21-21 and the back is a 5.10-18 I haven't used them yet because I wanted to see how the 606 was going to do, but I think after the Kenda tires I am going to go back to the 606 I really like the tire, haven't slipped once on the blacktop, and it adds an inch to the seat height.

 

If you are interested in selling the Kendas, shoot me a PM and/or email.

 

I just put the same tires Deej bought on mine the Kendas they fit fine and make the bike look like a 450 in size I have a need to balance the front tire its just a bit off

 

Only reason I can think of that he would say that is maybe he thought it would rub?
But as you know there are lots of guys here running 5.10 with no rubbing.

 

A wider tire might imply a taller tire which would tend to decrease torque at the rear wheel due to the slightly larger diameter. Seems like that would be a small effect, though. I ran 5.1x18 K270's and didn't have any problems to report.

 

Thanks all. Now if I can just get Deej to come off of those Kendas that he doesn't need or want! nudge, nudge, wink, wink?

 

A wider tire will have a wider contact patch, no nessesarily larger, unless you reduce the tire pressure. It's symple pyshics, if you have 150lbs supported by the rear wheel, and 15psi in hte rear tire, the contact patch will be approximately 10 square inches. Not exactly because the stiffness of the tire carcass and tread pattern will affect this as well by distributing the load.

A wider tire will disperse heat better, this is good if you're talking about slicks on the racetrack and are overheating your tire. A wider tire will slide smoother, and may have more bite on acceleration and braking. IF will also track better in the sand. IT may make the bike feel more stable at high speeds.

Otherwise, a wider tire will increase the affective gear ratio, make the bike harder to turn, have more rolling resistance and wind drag, cost more money.

 

motoguy128, you make some really good points there. Definitely some things I have not thought of.

Neglecting the obvious impact of tread design, would you think the sand performance of a wider tire would translate into mud performance? I know that I am speaking apples and oranges here, but my thought is that the wider tire would present more overall tread as well as spreading the downward force of my big butt over a larger area, thus reducing the tendency to sink instead of go over the mud.

My main goal is stability on the road in all conditions, especially rain. If I am getting a similar size, but different shape, contact patch with a wider tire, then I still think might be a plus. I would think a wider patch would be more resistance to a kicking out to the side in a turn versus a longer, narrower patch.

Ultimately everything may come close to cancelling out. It sounds like there is not one big reason to outright avoid wider tires, though. As Nobrakes points out, there are a lot of folks on this forum running 5.10s on the back. I just don't want to ignore the counsel of this experience shop owner.

Thanks all for the input. I will probably go for the 5.10. Right now it is sold out at DennisKirk.com, so I may be impatient and go for the 4.60 anyway.

Thanks,
Chris

 

wow,, thats way too technical just to pick a tire width..... just get the big one... big is better! lol