Author Topic: Is it a problem to put rear tires on the front? (Read 3642 times)

erb4 · « **on:** May 08, 2008, 04:39:02 PM »

I have found a set of tires that I like, however, the tire that's the correct size for the front is labeled as a rear tire in the catalog. Will this be a problem?

Thx
Ed

Gordon · « **Reply #1 on:** May 08, 2008, 05:08:54 PM »

It's best to ask the manufacturer. If they've designed a tire specifically for front or rear application, then IMO it's best to stick with that.

heffay · « **Reply #2 on:** May 08, 2008, 05:53:26 PM »

check out this thread...

http://forums.sohc4.net/index.php?topic=34140.0

DJ_AX · « **Reply #3 on:** May 08, 2008, 06:13:36 PM »

I heard that it does matter!
And the reasoning that I've heard that convinced me... (anybody please correct me if I'm wrong)
The rear tires are engineered to withstand more acceleration forces.
while the fronts engineered to withstand more stopping forces.
They pull in different directions on the sidewall...

HondaMan · « **Reply #4 on:** May 08, 2008, 06:30:13 PM »

You're right about the direction business: they run opposite on the different ends of the bike, and on a car.

On the CB750, in particular, front tire pattern is pretty important. The reasons are many and varied, but suffice it to say, the best handling will show up with a front-type tire on the front. If you install, say, a block pattern on the front, it will wiggle at speeds in the 30-50 MPH range, particularly when coasting down a hill or riding 2-up. And, this will be much worse if the drive chain is not silky-smooth. Air forks and solid bearings all around will also help, and check those swingarm bushings for less than 1/16" sideways looseness as well.

On the rear, it's not so important, other than to improve the wear, that a rear type pattern be used.

333 · « **Reply #5 on:** May 08, 2008, 07:07:09 PM »

Tread patterns also play a part in correct handling, especially when dealing with water shedding.

cbass*gxc · « **Reply #6 on:** May 08, 2008, 08:26:36 PM »

I would like to chime in here as well because I am getting ready to order new tires and have been doing some research today. I am wanting just the opposite. The tires I want are the Maxxis Classic Whitewalls and they only make fronts in the size I need. So from what you say DJ_AX, I can use a front on the rear but it will wear faster? I thought I read something about that earlier, but I wanted to make sure before I order tires.

Jay

Tower · « **Reply #7 on:** May 09, 2008, 11:13:54 AM »

As Handaman mentioned, motorcycle tyres are directional. Many will have an arrow indicating the direction in which they should be installed.

Aside from the tread differences, what is unclear, cbass*gxc, is when putting front tyres on the rear, should that direction be reversed. Its very likely that the rear tyre, in taking the brunt of acceleration forces which are in the opposite direction to the braking forces the front tyre takes, should have the plys laid in opposing directions.

There are also universal fit tyres which are non-directional. These tyres can safely be mounted front or back.

Tread patterns can either enhance or help defeat lateral forces. Different treads allow the front and rear to behave in a coordinated fashion. This is a major reason why front tyres should be matched to rear tyres, pattern-wise.

jasburbak · « **Reply #8 on:** May 09, 2008, 11:38:35 AM »

Quote from: cbass*gxc on May 08, 2008, 08:26:36 PM

I would like to chime in here as well because I am getting ready to order new tires and have been doing some research today. I am wanting just the opposite. The tires I want are the Maxxis Classic Whitewalls and they only make fronts in the size I need. So from what you say DJ_AX, I can use a front on the rear but it will wear faster? I thought I read something about that earlier, but I wanted to make sure before I order tires.

Jay

Hey, thats exactly what i did. I bought Maxxis Classic White Walls (fronts) and had them installed in the rear. Actually its being installed as i write this at the shop. I asked around quite a bit and some people say to reverse the direction when putting a front on the back.. However i've also heard, and when asked the shop guy that i should install it as the manufacturer recommended direction. I go with the second logic, due to the fact that the tread pattern if put in reverse direction would groove the water into the center and hyrdoplane the tires. Then again, i've been riding motorcycles for less than a month, so don't count on my logic, i listen to the experts as well....

As far as handling goes, i'll update you with how it is when i pick up the bike in a few hours, but i intend to ride my bike in the city, ~50mph and no sharp cornering, just cruising to class and around. So, no tough stuff, but i'm guessing since you want a whitewall on the rear "bobber style" you'll be doing the same as well...

I went with these guys after a price check around http://www.tiresunlimited.com/ALL%20TIRES/Maxxis/maxxis_classic_m6011.htm

great service, and had the tires within 3 days, cheapest around too!

Good luck.

jjwaller · « **Reply #9 on:** May 09, 2008, 12:31:24 PM »

You all do know, that Maxxis are just
Cheng Shins!. Cheap chinese stuff.
Wouldn't touch them. I stick to real tires.
Bridgestone or Metzlers.

John

kayaker43 · « **Reply #10 on:** May 09, 2008, 01:30:22 PM »

It was popular to run a 4.10x19 Dunlop K81 rear tire on the front and an 18 inch K81 on the rear. Just reverse the direction arrow, but I seem to remember it had two arrows, one for front and rear??

HondaMan · « **Reply #11 on:** May 09, 2008, 07:24:13 PM »

Quote from: kayaker43 on May 09, 2008, 01:30:22 PM

It was popular to run a 4.10x19 Dunlop K81 rear tire on the front and an 18 inch K81 on the rear. Just reverse the direction arrow, but I seem to remember it had two arrows, one for front and rear??

Mine said, "Direction of drive" on that arrow. "Drive" on the front is the braking action.
The Brits tend to be succinct like that...

jasburbak · « **Reply #12 on:** May 10, 2008, 12:05:33 AM »

For "cbass*gxc"

I rode all day today from 11am to 1am on the new Maxxis Classic whitewalls, so far no issues with handling, it did its job, no hard cornering, but i think it seems to get the job done!

Tower · « **Reply #13 on:** May 10, 2008, 01:45:07 PM »

@jasburbak, Next install, consider reversing the rear tyres direction. This will strengthen the sidewall against sheer force from acceleration and reduce the chance of sidewall failure. It does not mean otherwise your sidewall will fail. It just means that its less likely to fail when reversed.

Also, your rear tyres will wear much faster than the identical front - not simply because there is less rubber than on a comparable rear tyre, but also because the contact patch will want to "squirm" slightly in the direction the plys are arranged (when you accelerate and when you brake). Since this squirm inclination is in the opposite direction intended, that will cause fractional extra wear.

To your concern about water: Imagine a film of water on the road. Now as the tyre rolls over the film at high speed, its as if the contact patch was pressed onto the road. The pressure squeezes the water away. The grooves catch and channel the water, allowing the tread to make contact with the road surface. Regardless of which direction the grooves run, the tread will push water into them. The small patch of water under that pattern will move in all directions with equal force. Hence, it does not matter which direction the grooves run. For huge amounts of water it might be beneficial if the grooves ultimately opened up at the edges of the contact patch as that might increase their channeling capacity. Manufacturers know this and hence modern tyres have grooves that run every which way, but are wider near the centre than the edges as this increases their capacity under the contact patch.

The tyre becomes a "squeegee" when excess water builds up in front of the contact patch. And this happens if the grooves do not have sufficient channeling capacity (width and depth wise). The tyre, instead of making contact with the road, remains on a film of water, as the squeegee cannot push enough water aside before the tyres moves forward. Again, nothing to do with groove direction. All to do with groove capacity verses amount of water plus amount of squeezing time (speed) of the tyre.

cbass*gxc · « **Reply #14 on:** May 10, 2008, 02:00:48 PM »

^^ That is some useful info. So it is not a huge deal which way the rear tire tread runs.

jas - Good to hear. I am ordering mine on Monday. Woohoo! You got any pics of your bike? I would love to see some on our bikes.

Bob Wessner · « **Reply #15 on:** May 10, 2008, 02:54:16 PM »

Quote from: cbass*gxc on May 10, 2008, 02:00:48 PM

So it is not a huge deal which way the rear tire tread runs.

Not sure this is accurate as stated. All the MC tires I've seen have arrows on the sidewalls indicating the correct direction of rotation.

333 · « **Reply #16 on:** May 10, 2008, 03:18:37 PM »

Another reason to keep front on the front and rear on the rear is that the belts are laid diagonally for a specific reason. To do the job they were designed for. Yes, you can reverse tires, but do you want to. They get away with it on the race track because the tires are changed after a couple of races(at the most). They don't worry about what can happen to the belts when they bunch up because they are running the wrong direction.

In the case of white walls, don't they make the "paint"(I know it's not real paint) to make your own?

Tower · « **Reply #17 on:** May 10, 2008, 03:44:07 PM »

Good point, Bob. As a blanket statement this might not be accurate. In context to using front tyres on the rear its probably more accurate.

How treads are arranged can make a difference to a tyres performance and even to its hydroplaning characteristics, especially if a tyre has no centre groove but uses a pronounced V-shaped centre groove pattern. A single straight non connected centre groove acts like a water superhighway. Its an older design, proven to have hydroplaning issues. Also, a centre groove adds significantly to squirm and reduce tread stability and so, tends to be avoided in rear tyres and many modern tyres. Variations are better - such as multiple centre grooves and boxed or connected side grooves (I don't mean sipes, although some connected grooves can run to the sidewall and act as sipes).

A v-shaped centre groove acts best at water channeling if the point of the V is at the front of the contact patch.

Tyres that use diamond shaped grooves and or zigzag centre grooves tend to be more universal in direction and sculptured or curved grooves tend to be very poor at water channeling but much better at traction and stability.

You didn't think that tyre tread design was that simple, did you?

DJ_AX · « **Reply #18 on:** May 10, 2008, 07:36:24 PM »

If it didn't matter .. there would be no arrow.

Tower · « **Reply #19 on:** May 10, 2008, 09:01:16 PM »

The arrow has more to do with ply construction than tread pattern, although as we've argued here, in some cases, reversing the tread pattern could effect performance (regardless of ply construction). However, in many (most?) cases tread pattern is not an issue with respect to tyre direction (as for example in almost all automobile tyres).

jasburbak · « **Reply #20 on:** May 10, 2008, 10:07:38 PM »

Quote from: Tower on May 10, 2008, 01:45:07 PM

@jasburbak, Next install, consider reversing the rear tyres direction. This will strengthen the sidewall against sheer force from acceleration and reduce the chance of sidewall failure. It does not mean otherwise your sidewall will fail. It just means that its less likely to fail when reversed.

Also, your rear tyres will wear much faster than the identical front - not simply because there is less rubber than on a comparable rear tyre, but also because the contact patch will want to "squirm" slightly in the direction the plys are arranged (when you accelerate and when you brake). Since this squirm inclination is in the opposite direction intended, that will cause fractional extra wear.

To your concern about water: Imagine a film of water on the road. Now as the tyre rolls over the film at high speed, its as if the contact patch was pressed onto the road. The pressure squeezes the water away. The grooves catch and channel the water, allowing the tread to make contact with the road surface. Regardless of which direction the grooves run, the tread will push water into them. The small patch of water under that pattern will move in all directions with equal force. Hence, it does not matter which direction the grooves run. For huge amounts of water it might be beneficial if the grooves ultimately opened up at the edges of the contact patch as that might increase their channeling capacity. Manufacturers know this and hence modern tyres have grooves that run every which way, but are wider near the centre than the edges as this increases their capacity under the contact patch.

The tyre becomes a "squeegee" when excess water builds up in front of the contact patch. And this happens if the grooves do not have sufficient channeling capacity (width and depth wise). The tyre, instead of making contact with the road, remains on a film of water, as the squeegee cannot push enough water aside before the tyres moves forward. Again, nothing to do with groove direction. All to do with groove capacity verses amount of water plus amount of squeezing time (speed) of the tyre.

Thanks so much for taking the time to explain the concept, i heard of reversing the fronts when putting on the back, but didn't know why, much appreciated..

Quote from: cbass*gxc on May 10, 2008, 02:00:48 PM

^^ That is some useful info. So it is not a huge deal which way the rear tire tread runs.

jas - Good to hear. I am ordering mine on Monday. Woohoo! You got any pics of your bike? I would love to see some on our bikes.

Sure, i just got done washing and cleaning my bike too, just in time for a photo

I'll have a picture of it up tommorow afternoon, it looks absolutely great! I got a bunch of thumbs up and people gathering around to check it out when i parked for a bit... they do make the bike...

cbass*gxc · « **Reply #21 on:** May 12, 2008, 06:52:04 AM »

^^ Sweet I am excited to see them.

jasburbak · « **Reply #22 on:** May 12, 2008, 03:42:11 PM »

Here you go! It was raining yesterday, so i couldn't get a pic, but shot a couple today...

chrislib · « **Reply #23 on:** May 12, 2008, 04:15:32 PM »

nice hooligan-y-ish ride! Are those flipped bars (thinking of doing that myself)? very interesting tank art/paint/???

jasburbak · « **Reply #24 on:** May 12, 2008, 04:34:35 PM »

Quote from: chrislib on May 12, 2008, 04:15:32 PM

nice hooligan-y-ish ride! Are those flipped bars (thinking of doing that myself)? very interesting tank art/paint/???

Thanks! yeah, those are flipped bars, the paint job was done to make it seem worn out, it's got some pinstriping too on the top and sides...

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Author Topic: Is it a problem to put rear tires on the front? (Read 3642 times)

erb4

jasburbak

jjwaller

jasburbak

jasburbak

jasburbak

jasburbak