Sportbike Forums on WristTwisters banner

Tires – Directional Arrows?

1.8K views 16 replies 9 participants last post by  HondaJim  
#1 ·
Saturday I took my wheels in to the local KTM dealer to have him mount new tires. He mounts them for $25 when you buy them from the internet. I got 15,000k out of the Avon Azaros so I was ready. I bought a set of Michelin Pilot Roads for the 919.

I picked the newly mounted wheels up later on Saturday and took them home to install. I always look to see if the directional arrow on the wheel matches with the one on the tire, but should have done this before I left the dealer! The front doesn't! Now I have to take it back after work and "make" them do it while I wait (I'm not driving 10 miles through traffic to pick it up again).

How important is mounting the tire so the directional arrows match up with the wheel? Tire life, traction, "danger!", etc.

Thanks,
 
#2 ·
Minus rain... I have never heard of an incident. But the tread pattern in the front should look "backward" as it is designed to funnel water away from the centerline.

If mounted backward, this channel would possible make the bike a bit unstable. I have never heard of an incident regarding this... but it just seems like it would be the case.

I have run my race tires backward due to excesive wear on one side and trying to extend it life by flipping the tires around. Never an issue.
 
#3 ·
Two thoughts

If it was the Honda, just swap the axle spacers side for side. Ktm ,who knows try it and see if your discs line up with the calipers.
Right now I'm running my front tire backwards, for 1300 miles so far. I've got 8,300 on my tires and still have good deep grooves in the tread. The rain grooves were sharp on one end and rounded slightly on the other. The tire had picked up a small wobble with hands off riding. I flipped the tire to wear down the sharp edges and it runs smooth at all speeds hands off. I've rode on wet roads like this, but, not a driving rain. I've done this on several different bikes and I'm not scared of it. When the edges are smooth on both sides, I'll flip it back.
 
#4 ·
I spoke to a michelin technical expert at a seminar on tyre construction last year.

He said that the reason manufacturers had now "reversed" the tread on front tyres had nothing to do with water dispersion. Apparantly mc-tyres have so narrow a contact area they disperse water just fine even with no tread. Tread patterns have two roles; two allow flex and therefore let the tyre heat up more easily, and as a marketing tool. The reason they reversed their tread was that it reduced cupping. Previously the point or narrow part of the tread pattern was the first point of contact with the road and therefore wore faster than the wide part of the tread pattern.
 
#6 ·
I have a hard time with the water dispersion part. Slicks and water don't work well together.

BTW, Metzler has been running "reversed" tread for years.







I once mounted my tires on the rims backwards, then mounted the bike on the rims backwards. I had six reverse and one forward gear with front wheel drive!
 
#5 ·
i dunno about the front tire but i had mounted the rear tire on my 919 backwards once. (late night swap) well the next day on the way to work i felt it. when on power in the corners felt like it was sliding out from under me. swaped it around for the way home and it was much better.
 
#7 ·
I do not buy the reps answer either.

I have been caught on the back side of VIR with slicks when the rain decided to come down. It was the scariest trip down the roller coaster at 20mph. The bike walked all over and hitting the breaks were no longer and option.

And as far as a technical expert goes... he may be a carcass expert, he may be a rubber expert, he may just be a pen pusher that knows more than the average Joe. I have heard rediculous stuff come out of the mouth of guys mounting tires at the Dunlop trailer before.
 
#9 ·
Years ago I was told it had something to do with how the tire was 'laid' up.
Like rolling a roll of toilet paper, in one direction it stays on the roll the other
way it unwinds. I may be wrong but that's what I was told.

Later
Rich
 
#11 ·
I believe the laid up theory of the cords unraveling in tire construction was big news having to do with early radial tire developement mainly with cars.
Seems I remember this having to do with Firestone 500 tires and police interceptor vehicles wrecking caused by the unraveling of cords in the casing and the end result was a blowout at speed.
Good for the chasee bad for the chaser
 
#13 ·
Well, I took the front wheel back in and he mounted it correctly, apologized, and got me out the door in under 15 minutes.

While I was waiting I looked at all the KTMs on the showroom floor (KTM dealer). Does Ducati get heartburn when anyone mentions the KTM Super Duke? Nice bikes, but expensive.
 
#14 ·
When mounted the wheels back on the 9'er, and cleaned and replaced the chain, I noticed that the rear axle nut is not "safety wired"! All of my previous bikes had a cotter pin through a hole in the axle and the axle nut. I wonder why this was dropped, and "when" it was dropped? Granted, my previous bikes were generally of a different vintage:

1968 Honda CB350
1973 Honda CB450
1981 Yamaha XT250
1983 Yamaha XT550