67mph from my vectrix as tested with a Tomtom

Great idea -- darn I just replaced my rear tire too!

Just got my V back from a charger replacement. They updated the software while they had it there, and she'll do 68mph now (so I'm told). I've only ridden it once since getting it back, and it easily got to 65, but the traffic wouldn't let me "test" its limits.

nd she'll do 68mph now (so I'm told)

Anything else changed than only speed limiter?

Wow, that looks like a snug fit. Still, it will get better with time and miles! I guess a thicker tyre has a bit more give in it, which would explain the improved ride. Keep us up to date - I'll put a 70 profile tyre on mine next time if it's that good!

Brian

Therefore there's a new FW upgrade... oct 2008 to May 2010?

Yep, but I have no idea what the release date was for it. Dealer didn't say (probably didn't know anyway).

Anything else changed than only speed limiter?

Well, my clock went to 24 hour status, and I can't remember how to get it back to 12, but other than that, none that I can tell!! ;-)

I can't remember how to get it back to 12, but other than that, none that I can tell!! ;-)

Quick press of the H button should do it :-)

That's one way to get more speed without the software! Just remember your speedo is now reading about 8% low now so round it up to 10%, do some quick mental arithmetic and avoid any speeding fines from those darn cameras!! ;-)

This thread has been added to the Vectrix Collaborative Handbook, please stay on topic!

Just a thought...

Will the motor safely handle the increased forces that a larger (and heavier presumably) tyre will create? One for Doug and Steve perhaps...

Brian

Hi Drew,

That's good. My concern (which I didn't really get across effectively ;-) ) was the effect of the increased gyroscopic forces on the wheel / motor mountings, but I guess the swingarms hold it all in place and are pretty heavy duty. And I guess you would feel any odd behaviour in the handling round corners.

Cheers,

Brian

Be careful, 5mm clearance is very tight and the tyre may flex due to centrifugal force and road bumps. I would keep a close eye on both the tyre and the swing arm.

VectrixAddict raises a very good point that a tyre will grow (stretch and circumference becomes larger) as speed increases but if the tyre is inflated to 40psi I wouldn't think it would grow too much at 67mph. But do keep an eye on the swingarm for any sign of black rubber marks where the tyre has made contact.

The only place you may have contact is the underside of the trunk Drew.
I have seen this with a standard tyre especially with with a rider with a fuller figure ;-) plus cargo .
It Might pay to wind the rear shocks up a notch.

Despite being - ahem - a fuller figure, I've not bottomed out the rear shocks yet... So unless you're way north of 16 Stone Drew, I reckon you'll be OK...

The only place you may have contact is the underside of the trunk Drew.
I have seen this with a standard tyre especially with with a rider with a fuller figure ;-) plus cargo .
It Might pay to wind the rear shocks up a notch.

Waking-up this old thread...

I'm about to change my rear tire and am seriously considering going a size or two larger.

There is more than enough clearance on the fork and shocks to mount even a 150/70-13 tire. It is supposed to have 281mm vs. 257mm "centrifugal radius" on the stock 140/60-13 size (see specs on Pirelli Diablo Scooter online for this and other specs). This is 24mm difference (radius, 2x that in diameter).

I am not sure if the clearance under the seat is tall enough under load to avoid rubbing over bumps though. I'm close to 200lb and often have another 120lb and occasionally a 180lb passenger. To check for rubbing, I just fitted a 30mm thick foam piece temporarily under where I think the lowest clearance is under the seat. Will ride with over the next few days to see if it rubs against the current stock tire (which still has most of its thread but has other damage so it needs replacement soon). If it does not rub, or if it rubs less than about 5mm, I should be OK, is my thinking.

Lastly, the rim width on the Vectrix appears to be around 40mm (I don't know how to measure properly - does anyone know for sure?). 40mm is the recommended rim width on the stock tire and is just below the middle of the range for the upsized version I am considering (so fine for both, if it is indeed 40mm).

I'll update you on what I find.

The reason I'm considering a bigger diameter tire is that the 62mph speed limit does not quite cut it when everyone around me is going 65-70mph. I have the Laird's firmware, which goes with the old motor controller and the 62mph speed limit. Plus, the larger size can be used at a little lower pressure, which will give a softer ride and larger contact patch with the road for more traction.

According to an online tire calculator, 140/70-13 is only 3.4 miles per hour faster than the speedo, where the 150/70-13 is 5.1 mph faster than the 60mph on the speedo (i.e., the speedo shows 60mph, the actual speed will be 65.1mph).

Looks like I may have been overly optimistic about the "more than enough" clearance at the fork. Measured today, and there is 24mm clearance on mine today. That is exactly the increase in radius at speed with the 150/70-13 tire, so it will likely touch or fit to within a mm. Not comfortable with such a tight clearance.

Also, FYI, I rode deliberately faster than normal over some speed humps today to see how the rear compresses under a good load. Checked the piece of foam I glued under the seat above the tire. It was 35mm and it seems that is too much - it had rubbed against the tire a bit. So I chopped it down to 24mm today and will check for rubbing again in a day or to. If there is no rubbing there, this means there is at least 24mm clearance under strong compression, but again - it looks like a very tight fit for that larger size tire and will likely rub with two people riding over bumps.

So, I will have to go with the original size or possibly with the 140/70-13, but unfortunately, the brand and model I like does not come in this size and I don't want to get an "unknown" quality tire.

What did you have to modify? Any photos?

Also, how are these Bridgestone compared to the OEM Pirelli in terms of grip? Thanks for any info!

My V came with Pirelli GTS 24 in the rear that are no longer available in our size according the Pirelli web site. The front is a Pirelli Diablo and it rides fine. So I was going to get the Pirelli Diablo for the tear too.

The Diablo are supposed to be good sporty tires (if not terribly long-lasting). Plus, the Diablo in the 140/60-13 size comes "reinforced" (whatever that means, probably a bit more puncture-resistant).

Pirelli has a chart for recommended applications and the Diablo are on the sportier side of Sport-Touring (I read "stickier"), where the GTS are in the middle of Sport-Touring . They are close in that regards to the GTS but made for the largest and heaviest scooters, which I think is more where the Vectrix falls (it may run like a 125cc but weights as much as a 600cc).

I'll be very surprised if you can fit anything bigger than the 140/70 13. I ride on these all the time now and they're more comfortable than the original fitment Pirellis.

Maybe slightly amusingly, I am north of 16st (closer to 17!) and occasionally carry a pillion. In the end I had to modify the under seat trunk slightly so that I had enough clearance for full compression of the shocks, even though they were set to the highest setting.

Everything runs fine now and I wouldn't go back to the earlier size.

Best wishes,

Drew

The OEM Pirellis lasted 11000 miles for the original owner, but were bald in back and unevenly lumpy in front. I have just installed a 150/70 in the back (standard in front), both Avon Strykers (I chose them because they were S-speed rated, not that it will matter) - keeping it below 28psi gives enough clearance, but it is very tight. No scraping on bumps, and it is nice to be able to lean comfortably into a turn.

Did a run with GPS - both odo and speedo are 8% low. I have yet to take it out on the freeway, but that would equate to a top speed of 73mph.

Plus, the Diablo in the 140/60-13 size comes "reinforced" (whatever that means, probably a bit more puncture-resistant).

"reinforced" in tire/tyre speak denotes a higher load bearing capacity than a standard one of that size, i.e. it can be fitted to heavier vehicles.

Plus, the Diablo in the 140/60-13 size comes "reinforced" (whatever that means, probably a bit more puncture-resistant).

"reinforced" in tire/tyre speak denotes a higher load bearing capacity than a standard one of that size, i.e. it can be fitted to heavier vehicles.

Plus, the Diablo in the 140/60-13 size comes "reinforced" (whatever that means, probably a bit more puncture-resistant).

"reinforced" in tire/tyre speak denotes a higher load bearing capacity than a standard one of that size, i.e. it can be fitted to heavier vehicles.