The Case for the 15" Super Scooter Radials

[bikedave99]

Alright, and flame on! :biglaugh: Wait... naw, this isn't Pirate4x4...

Ok, I just want to have a frank conversation about the new crop of 15" radials which are becoming available for the ever expanding line of super scooters, and their use on the Vmax stock rear wheel. (why does it take a scooter in order to get the tire manufacturers to make a 15" radial...:bang head

So, the conventional wisdom is that the scooter tires do not have the load capacity for our heavy bike. I will be using the Metzler Feelfree 160/60-15 (67H) as an example. This Metzler tire has a load rating of 67, which means it can carry, at a maximum, 677lbs at its rated speed of 130mph.

Ok, so based on a google search, the vmax has a rear biased weight distribution of 44% Front -> 56% Rear. So, if the Vmax is about 630lbs wet, that means that without rider there is 353lbs on the rear. Adding the rider, i'll be over-cautious and assume that 80% of my weight (180lb dressed) is on the rear. So, the total load the tire would see is: 144lbs (80% of 180) + 353lbs= 497lbs. This is 180lbs shy of the max load rating for the tire.

Most of my riding is one up, and even if my wife were on board, we would be be 50lbs under the load limit and driving at half of the rated speed. Granted, it would probably not last as long... but would be a cheaper method of trying out radials. It could be paired with a Metzler Roadtec Z6, which its tread pattern is lightly based off of.

For comparison purposes, the Vmax user manual says to use a tire with a load rating of 74, or 827lbs, and that the maximum load that can be carried on the bike (people and gear) is about 475lbs. So, using the same math as above, the bike load on the rear is 353lbs, and 80% of the max load (2 big people and gear) is 380lbs for a total of 733lbs on the rear tire. This is 94lbs less than the max load rating.

So, trying to look at the options logically and with the numbers, someone who rides primarily one up or two up and stays under the load limit, the scooter tire seems viable and safe. Obviously, there are also advantages to aftermarket wheels due to reduced rotating mass, but that is a different, very well documented story.

Thoughts?

 

[sdt354]

That would be very tempting Dave. One of my biggest disappointments when I bought my bike and needed tires, was the lack of 15" radial tires and the cost of wheels to upgrade. H rated doesn't bother me at all. The radius of the wheel/tire will be lower. I'd lower my forks to keep the weight bias at least stock,if not more on the front wheel. Interesting, and about time. I was just talking to Wayne from N.H. about this a few minutes ago. I think I'd be temped to at least investigate this if trying to get radials on without breaking the bank.
Steve-o

 

[[email protected]]

That would be very tempting Dave. One of my biggest disappointments when I bought my bike and needed tires, was the lack of 15" radial tires and the cost of wheels to upgrade. H rated doesn't bother me at all. The radius of the wheel/tire will be lower. I'd lower my forks to keep the weight bias at least stock,if not more on the front wheel. Interesting, and about time. I was just talking to Wayne from N.H. about this a few minutes ago. I think I'd be temped to at least investigate this if trying to get radials on without breaking the bank.
Steve-o

Agreed

Id give it a shot.

 

[Heretic]

I'd like to hear your thoughts if you mount the tire, but I'm thinking that this won't be a very good tire on a Max. While it may physically hold the weight of the Max, I wander how the sidewalls will handle the increased force of the Max around corners under power. Its designed for a 40hp TMax, not a 140hp VMax. Its also a full three inches shorter than the 150/90 stock size.

 

[Rusty McNeil]

My guess is, and I could be really wrong, is that due to manufacturing processes that in order to make a 15" radial they don't really downgrade and go cheap on everything just cause its sized for a scooter.

It's just another tire size to them and probably would have the same integrity of any other tire they make.

I'd go for it in an instant.

Albeit cautiously with riding habits for a while.

 

[06VMAXIMUS]

Very interesting! I have always wondered why the tire companies don't offer a radial for the stock rim of our beloved vmax. For sure there would be a market for them with all the vmaxes on the road.

 

[one2dmax]

To maintain the stock ride height there is too much sidewall for a practical radial tire. Most radials have reduced sidewall heights which means less deflection and that's just another reason they are better handing.

 

[ninjaneer]

wow cool. id like to think im the adventurous type and volunteer with the ranks of the other guinea pigs, but hmmmmmm...

Regards from my Taptalking Hercules Android

 

[bikedave99]

I'd like to hear your thoughts if you mount the tire, but I'm thinking that this won't be a very good tire on a Max. While it may physically hold the weight of the Max, I wander how the sidewalls will handle the increased force of the Max around corners under power. Its designed for a 40hp TMax, not a 140hp VMax. Its also a full three inches shorter than the 150/90 stock size.

Can't argue with you Heretic. Thanks for the info on the tire height, I knew I was forgetting a variable for consideration. I knew it would be a shorter tire but didn't think it would be that big a difference. A lowered rear would make it less visually different I imagine. There is about a 10" difference in circumference between the stock tire and Metzler FeelFree, which equates to about a 12% reduction in speed at any given RPM. So, using a Venture diff would get you back to approximately stock gearing.

My guess is, and I could be really wrong, is that due to manufacturing processes that in order to make a 15" radial they don't really downgrade and go cheap on everything just cause its sized for a scooter.

It's just another tire size to them and probably would have the same integrity of any other tire they make.

I'd go for it in an instant.

Albeit cautiously with riding habits for a while.

Kinda my thoughts, take it easy for a while, possibly monitor the tire's temperature for a while to see how it is holding up.

 

[gamorg02]

I'd like to hear your thoughts if you mount the tire, but I'm thinking that this won't be a very good tire on a Max. While it may physically hold the weight of the Max, I wander how the sidewalls will handle the increased force of the Max around corners under power. Its designed for a 40hp TMax, not a 140hp VMax. Its also a full three inches shorter than the 150/90 stock size.

To maintain the stock ride height there is too much sidewall for a practical radial tire. Most radials have reduced sidewall heights which means less deflection and that's just another reason they are better handing.

this. i fully believed a lot of the rear end wiggles were due to the big ass tire sidewalls. lowering the rear that much may have a big difference on rpms, top end, and cruisability at highway speeds. maybe offest with a venture diff but i mean its probably going to be about 12-17% higher.

I noticed a big enough difference with the 190/50/17 on my rear.

 

[paulibiker]

Heck, some of those big scooters weight almost as much as the Max. I think it would be fine.

 

[Redbone]

I believe tires are constructed according to there load capacity/ range. So that would make me leery of using a scooter's tire on a Vmax weight, although there are some pretty big scooters out their nowadays.
EDIT: I now see where Heretic had already brought this aspect (no pun intended) of the weight concerns.
EDIT #2: Now Paulibiker has me covered too! Cold meds sappin' my already limited mental capacity!!!

 

[bikedave99]

To maintain the stock ride height there is too much sidewall for a practical radial tire. Most radials have reduced sidewall heights which means less deflection and that's just another reason they are better handing.

Ah ha! I don' t know how I have missed this information for years... so the advantage of the radial is the reduced sidewall height, the thereby flex! So, if the having a large sidewall radial would mostly negate the benefits it would bring, then I understand whey the manufacturers haven't done it. So, now the questions is, why didn't Yamaha increase the wheel size oh say.... 10 years into the production run? Thanks for the lesson Sean, makes more sense now. Not to say I won't test one of these smaller radials when my rear wears out...

 

[one2dmax]

The reason they didn't change was cost. They already had the casting molds made for the current wheels. Cheap asses.

80mph comparisons in 5th gear
150-90-15/stock rear diff = 4933rpm
150-90-15/venture rear = 4440rpm
160-60-15/stock rear diff = 5600rpm
160-60-15/venture rear diff = 5044rpm

Would be a great drag racing size actually!!
Top speed with 160 tire and stock diff is 136 in 5th at 9500rpm (168 with our overdrive lol)

Sean

 

[bikedave99]

The reason they didn't change was cost. They already had the casting molds made for the current wheels. Cheap asses.

80mph comparisons in 5th gear
150-90-15/stock rear diff = 4933rpm
150-90-15/venture rear = 4440rpm
160-60-15/stock rear diff = 5600rpm
160-60-15/venture rear diff = 5044rpm

Would be a great drag racing size actually!!
Top speed with 160 tire and stock diff is 136 in 5th at 9500rpm (168 with our overdrive lol)

Sean

True enough, but apparently they had the molds for the XJ900S Diversion which is exactly the same hub (different "spokes"). The do plenty of other cross-platform sharing... My old Virago had a ton o the same parts as my max does. Rediculous!

Thanks for running the numbers on the speed and verifying the Venture diff with 160 tire would be pretty close to stock tire and diff. The only I'm not sure of is if a 60 profile tire would make the rear end look a little panzy... I'm sure a lowered rear would help.

 

[naughtyG]

Sure sounds like a great tire size for drag racing and wheelies, but ol' Max will be awefully low, as in not very much ground clearance at all.. And those revs will be real high when cruising!

 

[gamorg02]

maybe it'd go well with some ZRX shocks? or some larger than stock length progressives.

 

[m-cman]

maybe it'd go well with some ZRX shocks? or some larger than stock length progressives.

Would sure look funny though! HUGE gap between tire and fender... :biglaugh:

 

[gamorg02]

Would sure look funny though! HUGE gap between tire and fender... :biglaugh:

that and 7k rpms at 55 mph!

 

[satariel666]

that and 7k rpms at 55 mph!

Sorta like speed limiter :rofl_200: