427FE
Active Member
I've seen several post to better the Gen 1 handling to get wheels that can use radial tires. Do radial tires not work properly with the Gen 1 stock wheels?
Radial tires on Gen 1 stock wheels
- Thread starter 427FE
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only front wheel there's no 15 inch radial tires for the stock rear wheel . you have to get an aftermarket wheel in a 17 or 18 inch which i have few if interested
Get your Big billet brace between the forks, some solid motor mounts and weld in frame braces. That'ill tighten'er up right nice.
A Radial up front with bias out back doesnt sound too kosher, maybe some tire experience can chime in in this one.
StanVM2007
Well-Known Member
I'd stay away from 17 inch rear tire - the speedo will not be showing correctly. I'd go for 18" if you decide to go for it. I think 18 - 5.5 would be a good choice. Maybe because I have it L0L 
There was a Sportster I think that used a mix of bias & radial tires, but I wouldn't do it on a VMax. I wouldn't use two different manufacturers' radial tires, or even two different rubber compounds. The method of construction of radials can be different (the angle of plies one to another) so that is something to look for. An example: one ply at 90 degrees to the bead is called 'zero degrees' while an oblique angle <90 degrees of the ply to the bead is called-out by whatever angle it is, '30 degree or 45 degree.' Careless mixing can cause a truly evil handling bike.
If you run for acceleration and you don't mind the higher rpm's then a 17" rear wheel can give you more acceleration. Bear in mind that two bikes putting out similar HP, the 17" rear wheel will get through the 1/4 mile faster but will be surpassed on top end by the bike w/an OEM 15" (taller) rear wheel.
If you run for acceleration and you don't mind the higher rpm's then a 17" rear wheel can give you more acceleration. Bear in mind that two bikes putting out similar HP, the 17" rear wheel will get through the 1/4 mile faster but will be surpassed on top end by the bike w/an OEM 15" (taller) rear wheel.
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? The speedo runs off the front wheel.I'd stay away from 17 inch rear tire - the speedo will not be showing correctly. I'd go for 18" if you decide to go for it. I think 18 - 5.5 would be a good choice. Maybe because I have it L0L
StanVM2007
Well-Known Member
L0L Yes. And with a 5 inch wheel you'd probably run the engine at a red line doing 20 miles and hour and wondering what the hell is going on - an example just to paint the picture. But great acceleration! - maybe if you'd compensate with a 5 foot wide tire for grip? Hahaha What it meant is the relation between engine rpm's (and rear tire rotations) and the bikes speed, shown on speedo correctly, will change. So, again, looking at this the other way, if you like cruising around at certain speeds will make the engines rpm higher at that speed. Bringing them down will lower the speed, and you will want to keep the engines rpms lower. With different sizes rear tire rotations will change. So, at the receiving end, while working correctly and showing the correct absolute speed - it will be showing a relative error. Two bike with different wheel/tire sizes will show different speeds under identical working conditions. In other words, you want be able to judge the speed by keeping an eye on the tacho as you used to relate them.
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StanVM2007
Well-Known Member
Check this out. It will tell you the exact error and speeds, and you can even do comparison to stock tires.
Tire Size Calculator
Tire Size Calculator
jimbojones132
Active Member
"There are H rated radial tires in 15" just be sure to run both f & r bias-ply or both radials, same construction, same compound."
Sound idea.
Sound idea.
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There are H rated radial tires in 15" just be sure to run both f & r bias-ply or both radials, same construction, same compound.
StanVM2007
Well-Known Member
With all due respect, I think you missed the point I was making. I will try to explain to my best ability.
It doesn't matter what one is driving by. For example, I mostly drive by the sound and feel of the engine. The tach is just means to measure and see one of the engines parameters, and the speedo is another to measure the 'traveling speed' relative to the environment. Then you have the wheel - which is mechanically the final receiver of what the engine produces. The wheel/tire rotates and moves the bike - and the speedo shows how fast. That's all.
In a way, you could look at the wheel as the last final gear, working not much different than any pairs of gears in a transmission. How so? It works between the final axle, aka 'pumpkin', and yes - the earth. You are actually trying to move the earth with your wheel riding a bike. The earth will not move of course, because of the unmatched difference in mass, so you are ending up riding a bike instead (thank you thin air!). But the principals are the same as if talking about two gears in a gear box.
Now, what would be a constant here? The stock or modified engine, and the output. Attaching different wheels will change how the whole motorcycle behaves (just like in a gearbox attaching a different sprocket would create different ratio). Including speed and 'traveling speed' relative to how the engine goes through gears. Heavier wheels, lighter, wider or narrower, tire rubber, etc. - all will impact how the bike behaves. Including - the wheel/tire diameter!
The whole drag and speed racing industry revolves around a lot of science, specifically tweaking not just engines, gears and so on, but also suspension and wheels. The Vmaxers talk a lot about fractions of a second in 1/4 mile, and lots of guys do expensive all sorts of mods, carb mods, to squeeze that 0.1 second out. Why would you ignore something as straight forward as a wheel size difference and what change it brings? Different tire size will affect gear changes, top speeds, but also leisurely cruising and fuel consumption. That’s me. No drag strips. But man, if you are after 0.01 or even 0.1 second, performance control, that should be on the table.
But even for me, I’d rather change gears less often in city traffic and traveling at certain speeds on a highway, I prefer less engine rpm's and less fuel consumption.
The last paragraph is to illustrate what I am talking about, in case someone didn't bother to explore the science. This is a calculator that should give a general idea, guidance in choosing tire sizes. You can also do this calculation in miles.
Look at the Revs/km (or mile) numbers, and speedometer comparisons, which are called 'speedometer error'. It doesn't mean speedometer works from the rear tire or will start acting up erroneously! That's just silly.
Hope this helps and I really wouldn’t know what else could I add more here, unless trying to write a book L0L
1 - stock 150/90-15 vs. 180/55-18 – revs/km 489 vs. 486, 90 km/h vs. 90.7 – close to stock, nearly identical
2 - stock 150/90-15 vs. 180/55-17 – revs/km 489 vs. 521, 90 km/h vs. 84.7 – quite different
3 - 180/55-18 vs. 180/55-17
It doesn't matter what one is driving by. For example, I mostly drive by the sound and feel of the engine. The tach is just means to measure and see one of the engines parameters, and the speedo is another to measure the 'traveling speed' relative to the environment. Then you have the wheel - which is mechanically the final receiver of what the engine produces. The wheel/tire rotates and moves the bike - and the speedo shows how fast. That's all.
In a way, you could look at the wheel as the last final gear, working not much different than any pairs of gears in a transmission. How so? It works between the final axle, aka 'pumpkin', and yes - the earth. You are actually trying to move the earth with your wheel riding a bike. The earth will not move of course, because of the unmatched difference in mass, so you are ending up riding a bike instead (thank you thin air!). But the principals are the same as if talking about two gears in a gear box.
Now, what would be a constant here? The stock or modified engine, and the output. Attaching different wheels will change how the whole motorcycle behaves (just like in a gearbox attaching a different sprocket would create different ratio). Including speed and 'traveling speed' relative to how the engine goes through gears. Heavier wheels, lighter, wider or narrower, tire rubber, etc. - all will impact how the bike behaves. Including - the wheel/tire diameter!
The whole drag and speed racing industry revolves around a lot of science, specifically tweaking not just engines, gears and so on, but also suspension and wheels. The Vmaxers talk a lot about fractions of a second in 1/4 mile, and lots of guys do expensive all sorts of mods, carb mods, to squeeze that 0.1 second out. Why would you ignore something as straight forward as a wheel size difference and what change it brings? Different tire size will affect gear changes, top speeds, but also leisurely cruising and fuel consumption. That’s me. No drag strips. But man, if you are after 0.01 or even 0.1 second, performance control, that should be on the table.
But even for me, I’d rather change gears less often in city traffic and traveling at certain speeds on a highway, I prefer less engine rpm's and less fuel consumption.
The last paragraph is to illustrate what I am talking about, in case someone didn't bother to explore the science. This is a calculator that should give a general idea, guidance in choosing tire sizes. You can also do this calculation in miles.
Look at the Revs/km (or mile) numbers, and speedometer comparisons, which are called 'speedometer error'. It doesn't mean speedometer works from the rear tire or will start acting up erroneously! That's just silly.
Hope this helps and I really wouldn’t know what else could I add more here, unless trying to write a book L0L
1 - stock 150/90-15 vs. 180/55-18 – revs/km 489 vs. 486, 90 km/h vs. 90.7 – close to stock, nearly identical
2 - stock 150/90-15 vs. 180/55-17 – revs/km 489 vs. 521, 90 km/h vs. 84.7 – quite different
3 - 180/55-18 vs. 180/55-17
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jimbojones132
Active Member
I thought once upon a time I tried to find a radial for the OEM 15" rear and they said there wasnt one; however, they were trying to exactly match the size.
Does someone currently make a 15" Radial that's identical dimensions to OEM? If not, is there a slightly different sized radial that would fit that OEM rim?
Does someone currently make a 15" Radial that's identical dimensions to OEM? If not, is there a slightly different sized radial that would fit that OEM rim?
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Yes there is, but not in a 150/90 profile, and not V speed rated (to 149 MPH), but H (to 130 MPH) rated. How often do you ride over 130 MPH and for how long?
I for one would like very much to know who makes a 15 inch radial? thanks
There's a 15 "radial, but there for 100cc plus scooters. There's nothing that would match the height of a stock rear.
Last I looked (been a few years), agree with this. It was for a Tmax scooter and probably not well suited for the Vmax weight.
Mark
jimbojones132
Active Member
Would like to know more details on what make/model this tire is...thnx
A 30 second search and you’ll find more information than you need
jimbojones132
Active Member
I did search...and it brought me here. Someone offered general info and since they seemed to know, asked them for details...seems reasonable enough.
I have one in my storage, but I need to look to see whose it is. Hard to do as we're in San Antonio for a vacation. As I recall the profile is nowhere near the 90 series.
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