Topic: Effect of tire width on grated bridge deck or grooved pavement

[Cannibal]

Just curious if anyone has any experience or comparisons for the width of tires and their relative performance on grated bridge decks and grooved pavement?

The reason I ask, I have some crappy Chinese Kenda tires on my bike and am looking at replacing them with a quality Dunlop/Bridgestone/Pirelli/Avon tire (leaning toward BT-45 Battleaxe). I currently have 110/90-19 and 120/90-18. I may, at the same time, save some pennies for some flanged alloy rims. If I do so, I can always go with a WM4 on the rear so I can fit a 130 or maybe 140 rear tire, or stick with stock WM2 front and WM3 rear and go back to stock sizes.

I'd imagine that narrower tires would tend to follow grooves and grates more-so than a wider tire. Is there any truth to that? I ride over a grated bridge deck every day. I loosen my grip, relax my upper body, tighten my knees, and take a deep breath when crossing it. My current tires really make the bike wander around under me and the last thing I want is to make that worse.

Thanks for your input,
Steve

PS, I know the tire width topic has been beaten to death, but I've yet to see any discussion on their (ill?)effectiveness on these surfaces.

[eldar]

Well I can say the while tire width will cause issues but pattern will too. Ribbed tires are great for following tracks and grates. Don't knock the chengs too much. They do ok unless old but that is true for every tire. I have 110/90 19 on my front and they are bridgestones. They work good but follow grooves too. Just the nature I think.

[Cannibal]

Actually eldar, you bring up one more thing I wanted to mention; ribbed tires. My current tires are not ribbed, infact here is a pic (img from J.C. Whittless)

[rhinoracer]

My comment is not related to tire width, but tread pattern has a lot to do with the bike following rain grooves. That's as far as my experience goes.

Tires with a straight groove around the center will follow the rain grooves in the concrete, in fact it'll take a deliberate motion to get the bike out of such groove. Not so with zigzag patterned center grooves.

If you're sure the problem is in your tires, get a different set that'll make you feel confident. After all you shouldn't have paid too much for those Kendas.

However tire width does have an effect on tire temperature, wider tires on smaller bikes will not get warm enough to stick to the pavement.

[scondon]

 In my experience tire pressure, front/rear suspension and alignment have a far greater effect on the "oh my god there's a hinge in the middle of my bike" phenomenon than tire width/type does.

    Anything under 32psi starts loosening my hinge. leaky fork seals? Fix'em and be happier for it as unequal volume or one fork being filled with a milky viscous substance and the other with tired oil can have the bike wandering about in the smallest of grooves. Check the swingarm for play? notch in the steering bearing race? Shopping for the 'perfect' tire becomes a real quest if these aren't addressed first.

   May be that I'm just getting used to traversing grated bridges by now, but fixing all those things and keeping an eye on the psi has it that I haven't bought a tire in a long time with the thought that it would "track" less violently than another type. 4.00 rear and 90/90 front seem to handle the grooves just as well as 120/90 rear and 100/90 front. Arrow straight!  OK, ok, a kinda crooked arrow but man what a difference from the "hang on for dear life" days

[Cannibal]

Thanks for all the replies....

Guess I should have mentioned, this is my first bike....ever, maybe I've just got to get used to it. I've replaced the neck bearings and had them too tight to begin with, but after some searching on here, figured out how to set them, now, with the front tire off the ground, the front end goes smoothly from side to side with just a little push to start it from center, but without any play.

I've aligned the rear tire, I had that misaligned too when I did the chain adj, and now that's spot on using some string, not just the marks. Swing arm feels good too. Tires are set to 30front, 35rear. I figured with my weight (250lbs), a bit extra in the rear would be good. I will play with the pressure some more and see if the handleing changes.

Got the bike for $800 with these tires on them. Probably less than 500 miles on them so far. I should be able to sell them to recoup some of the new tire $.

Steve

[scondon]

  Good deal on the bike Cannibal

   Not sure what the pressure rating is on your tires, but 40psi max tires seem to be the most common. With these types 32psi front and 36psi rear is about the minimum I go and that is when I know that I'm going to do some hard, tire heating riding. Normally go with 36 front and 38 rear. Everybody has a preference about what they like their tires at so don't take my opinion as anything solid. I will go out on a limb and say that 30psi is low enough to be contributing to tracking issues. I'm pushing 250lbs fully geared

    Being a "big" guy I also set the rear shocks at a stiff setting which seems to help a bit with bike stability. More noticeable in the turns but also in straight riding on uneven surfaces.

    If bike is new to you then maybe change out the fork fluid just so you know you're at a good starting point. If it's old and/or contaminated then you should notice some improvement in front end stability.

 Grated bridges are what they are, but with all the bases covered they are certainly a lot less daunting. Though I lean towards Pirelli and Avon I don't think you can go wrong with any of the tire choices you mentioned. I've never tried the Bridgestone BT's but a lot of folks here swear by 'em.

Enjoy the ride and welcome to the forum

[DarkRider]

Personally i run 35 F/R on pretty much all my bikes...seems they track better at that pressure..

[neil10]

My last battleaxe good grip wore in 9000 miles  now on lasertec  good grip seems to start with more tread hoping for longer life

[KB02]

As far as the whole grooved pavement things goes, I would have to say that yes, a slightly wider tire does make a bit of a difference. The difference is not HUGE, but it is there. My Ducati, which runs a 160 in the rear, still wiggles around a bit on grooved pavement. My wife's CB400T wiggles around a good deal more. You've got to remember that your contact patch is really not much more that a couple of square inches, if that, even on the biggest tires (when properly inflated).

For what it's worth...

[eldar]

You all have not seen the grooves they like to put in the concrete here.  I have no experience with metal grate bridges as there are none left here but they sure like to groove the road for no good reason. I really love the older sections of concrete!

[Jonesy]

I just crossed the Mackinac bridge two weeks ago with my CB750 and the ribbed pattern front tires I have (Conti RB2) wobbled like crazy on the grating. Scared the crap outta me... 

[eldar]

That would suck. I have a groove going around my tire too. Just one but I am sure that is all it takes to start the wobble.

[scondon]

You all have not seen the grooves they like to put in the concrete here.  I have no experience with metal grate bridges as there are none left here but they sure like to groove the road for no good reason. I really love the older sections of concrete!

   My commute home comes to an end as I emerge from the Caldecott Tunnel that runs through the Oakland hills. Before me is a giant, sweeping "S" turn that drops down into the lowlands. Two empty lanes magically appear on the left and I am almost guaranteed a ride through the turns with no cars in front or adjacent to me. The wide open view of the bay with SF, Bay Bridge, and Golden Gate in the distance is still awe inspiring even though I've seen it a million times.

    Then some mother#$%*ing cracksmoking #$%*tard at CalTrans had the brilliant idea to groove the road. First time I hit it I thought my rear tire had gone flat and I pulled to the side to puzzle over what had happened to my bike. Thus begun the quest for a more solid ride. Happy to say that now those grooves just serve the purpose of telling me it's time to break out the pressure gauge and hit the air pump at the Shell station

[Cannibal]

Luckily they don't do much grooving up here in Washington, but do groove when repaving. There are some grooved roads here and there, just not around me.

Thanks for all the info, I'll give a few things a try and see if it makes much difference. If not, I still might replace these tires, especially if I go with alloy rims. These sizes I have now seem to work well in most situations.

Steve