Tire Question

[wjmark]

Bought my Wave 125 with 19,000km on the clock. Have put another 19,000km on it and have always loved it.

Even made Mae Sai to CM in 3hrs 20min two years ago. Hit 133 downhill.

Still runs great. But I have had two-and-a-half-year-old skinny Dunlop tires on it.

I bought a new CBR150 a few months ago, and with its big fat juicy tires, I just love how stable it is moving at 1km/hr between stopped red-light traffic.

So for my Wave, I bought the biggest tires the shop said would fit 70/90 and 80/90 (I think I could have put a 70/100 on the front).

It feels like a different bike completely.

Solid on the road and stable. (I had decent Dunlops on before, but the shop said that the IRC's were much better in the rain!).

About 1300 baht installed, and I have a new bike!!!! (okok, maybe it is not a CBR, but it sure feels different than a Wave)

Why do they have such skinny tires on these little bikes? Fuel efficiency? Do they actually handle better with skinny tires? I know some people race on the skinniest tires.

Any drawbacks to bigger tires on the Wave, other than losing a little power/fuel-efficiency (greater moving mass)? Is it more dangerous in any way? Is there any situation that I could slip more easily because of the greater width?

Cheers, Mark

[dave_boo]

Bought my Wave 125 with 19,000km on the clock. Have put another 19,000km on it and have always loved it.

Even made Mae Sai to CM in 3hrs 20min two years ago. Hit 133 downhill.

Still runs great. But I have had two-and-a-half-year-old skinny Dunlop tires on it.

I bought a new CBR150 a few months ago, and with its big fat juicy tires, I just love how stable it is moving at 1km/hr between stopped red-light traffic.

So for my Wave, I bought the biggest tires the shop said would fit 70/90 and 80/90 (I think I could have put a 70/100 on the front).

It feels like a different bike completely.

Solid on the road and stable. (I had decent Dunlops on before, but the shop said that the IRC's were much better in the rain!).

About 1300 baht installed, and I have a new bike!!!! (okok, maybe it is not a CBR, but it sure feels different than a Wave)

Why do they have such skinny tires on these little bikes? Fuel efficiency? Do they actually handle better with skinny tires? I know some people race on the skinniest tires.

Skinny tires do handle a bit better, simply because they have less mass so they turn faster. However, they don't absorb bumps as well. They have lower rolling resistance, so their fuel consumption is lower. Not significantly from what I've seen, but it's there. Also spinning smaller tires takes less power, allowing more to be transmitted to the ground.

Any drawbacks to bigger tires on the Wave, other than losing a little power/fuel-efficiency (greater moving mass)? Is it more dangerous in any way? Is there any situation that I could slip more easily because of the greater width?

You might want to check out your brakes status. Having greater mass to slow down will be rougher on them. Also, it's greater unsprung weight, so it will take more effort to affect steering. This could be an issue, but I doubt it.

Cheers, Mark

[PeaceBlondie]

To add to dave boo's excellent and technical answer, I would go back to the design of the Honda Wave - designed to be little more than a motor scooter, with lots of compromises. Buying my new CBR150R yesterday, I sat on the much better (than a Wave) Sonic 125. Disk brakes, alloy wheels, five speeds, etc. - still just a scooter. The Wave's engineers were not worrying too much about lean angles and tire mass and unsprung weight. Worrying more about how to design the pillion to fit Aunt Masayachapadula, her baby, and 8 durian.

[Richard-BKK]

Sorry people I fully disagree, skinny tires, under the factory specifications are seriously not recommended. Skinny tires are indeed better on a tights circle, but make the bike also very aggressive on riding. Meaning skinny tires make touring riding very discoverable.

Skinny tires also have in Thailand the mystery of providing lower fuel consumption, this story is completely irrelevant, over 200km the difference between the smaller road contact of the skinny tires and the bigger contact of the regular tires saves not fuel consumption. Matter of fact the skinny tires are less fuel economic.

Breaking power, a motorcycle like an 116kg CRB-150R will excite the breaking of its buddy on regular tires. At top speed this can difference in about 2 meters.

Even in racing, skinny tires lose to any bike running regular track tires; the skinny tires lose on breaking timing and power to road capability.

It started in Asia as bike ‘scooters’ did not had enough power or mass to get into a corner and therefore the mass ratio was also a bit off. Going into a corner with 120kilo (including rider) and getting out not need a lot on a modified 125cc Wave engine. With power like this you not talk about power you talk about movability and the best who can handle a bike under this almost impossible situation is the winner.

I had one client who installed very skinny tires on his CBR-150 and I was unable to ride it for fun, it was for the 2 km I ride it all stress, everything from cigarette bud to the smallest crumble I the road you feel as major problem.

My advice never, if you care your live go under the specs of tires the manufacturers specify.

[wjmark]

Thanks everyone.

Still enjoying the fat ride! (Is that "phat" in modern English?).

It might be a teeny little bit slower off the line, but it is hard to tell - still fast enough to leave things behind if I give it full gas.

The other thing cool about these IRC tires is that they are exactly the same model as the CBR, but smaller. So it is neat to see both bikes from behind.

But still curious about the wider tires and safety.

Is there any situation where I have less or unpredictable handling with the wider tires?.

Wider tire = greater contact area, but I think it means less contact pressure (same weight, but greater area = less pressure per square cm.)

In Canada, everyone knows that skinny tires are best for cutting through snow.

Any immediate and obvious problems with wider tires?

[Ramon88]

Big tires = more friction = better braking = more likely to keep you alive. Yeah, little tires might mean increases in maneuverability, but still less friction, thus more likely to slip out from under you when hitting a little patch of gravel, oil, water. That decrease in friction is exactly why the racers you see around here all have the little tiny bicycle-type tires on their bikes. Gets them up to speed more quickly - but SOL if they need to stop quickly.

I've always put bigger tires on my bikes - for the last 40 years. If you are worried about fuel consumption change the front or rear sprocket size to get the rpm lower at the speed you spend the most time driving, keep your chain well lubricated and tensioned properly (shops here tend to wayyyy over tighten chains for some reason, which quickly wears the sprockets and stretches the chain - and wastes lots of power).

Most people use their bikes for regular transportation in non-extreme situations, not for racing.

Edited May 18, 2008 by Ramon88

[PeaceBlondie]

I believe that extra wide tires on narrow rims get distorted profiles.

I swapped the 80/90 IRC on the front of my CBR150R for a 90/80 Dunlop about three months ago. That maintained a rolling radius of 72 mm, therefore no change in the outrageous speedometer error.

wjmark, do you have your numbers reversed, or do I? I think a 70/100 would be much too tall and not wide enough.

I am tempted to swap my brand new IRC tires on my brand new bike for wider Dunlops, but I found the Dunlops to be good quality.

[wjmark]

wjmark, do you have your numbers reversed, or do I? I think a 70/100 would be much too tall and not wide enough.

The reason I said that, is that AFTER I did the swap I found out that the original fronts are 60/100 (in the Philippines they come with 70/100)

Thai rear is 70/90 and in the Philippines they are 80/90

So w/ 70/90 and 80/90, I actually have smaller tires than stock Wave 125 in the Philippines...

http://www.yingyongmotorcycle.com/Honda/Wave125S.htm

http://www.hondaph.com/products/motorcycles/cubs/wave125s