Check your tire pressure it makes a big difference

[scooter7878]

So my scoot has been a bit slower lately I wasent sure what was causing the loss but I know tire pressure will make a difference but I really didn't think this much. My 139qmb stroker will usually hit between 55 and 57 flat no wind no tuck I was having trouble keeping 50 lately I found a slight leak in both intake and exhaust valves which I fixed and it got a little better power wise but not too end. I randomly just checked my tire pressure today and they were at 30psi. Max pressure is 40 and I usually run 40 I pumped them up and low and behold I'm hitting 57 to 59 flat no wind and yes it's gps verified. Point is I was surprised at that big of a difference in speed 10 psi made. I'm sure my gas mileage will be a good bit better too

[aeroxbud]

There is a lot of difference between maximum pressure, and recommended pressure. You are compromising grip for speed.
The contact patch on the road is less. As is the tires ability to do it's job.
Pedparts did an interesting article on tire pressure and performance. www.pedparts.co.uk/blog/effect-of-moped-tyre-pressures-on-performance

[scooter7878]

Aug 29, 2021 5:25:42 GMT -5 aeroxbud said:

There is a lot of difference between maximum pressure, and recommended pressure. You are compromising grip for speed.
The contact patch on the road is less. As is the tires ability to do it's job.
Pedparts did an interesting article on tire pressure and performance. www.pedparts.co.uk/blog/effect-of-moped-tyre-pressures-on-performance

I agree with that but u haven't had any trouble with traction even on wet roads I keep my tires pretty new I replace well before there worn and I run a wider tire so there's more rubber in contact but I fully agree with that and if I was having traction trouble I'd for sure lower pressure

[scootercy]

Mine is supposed to be at 25 cold, as I dont have a compressor within "cold" distance I set at 27 on hot tires, and boy there is a difference between 24 and 27 on speed. Guess with the smaller the motor the bigger differences in the drivetrain make.

[badmotorscooter]

As a scooter has a rear weight bias I run 5 more psi on the back tire. I weigh about 160 lbs and find 31/26 to be a good compromise of comfort, performance and traction.

Yes, I have tried running higher pressures for performance and you can notice a difference. But you also suffer from a much harsher ride and a significant reduction in traction.

It only takes one incident where you need all the traction you can get to realize a little extra top end isn't worth it...

[scooter7878]

Let me rephrase this my point was not saying for everyone to run 40 psi it was more meaning the difference in tire pressure makes a big difference so whatever u decide to run check them if ur experiencing speed loss. I'm a auto mechanic for 30 years and fully understand the pros and cons of tire pressure I just felt that was a fairly large loss of speed from 10 psi

[woodini]

I dig it.

[collinsd84]

30 has been my rule of thumb.
Balance might b the word?
Just b careful out there.
Traction v/s performance, be careful out there.

[jbjhillbilly]

Interesting.

I feel like I have less control on curves at speed with ~30psi vs 35-40psi. Not arguing or advocating for higher pressures, just that the bike feels wobbly at 30mph around a sweeping curve if it’s at a lower pressure.

Or is that more to do with technique?

[aeroxbud]

You would be surprised how much flex is designed into a tyre. This is intentional. That's probably what you are feeling.
By running higher pressures, you are eliminating this movement. But also limiting the tyres ability to work correctly.
Technique could also be to blame. My typhoon hates the way I ride. I like to brake hard, turn in fast. The budget suspension gets well out of shape. Even had a couple of massive handle bar shakes, and pogoing.
If I set up for the corner, let the brakes off, then lean. It's much smoother and faster.

[collinsd84]

Sept 5, 2021 2:28:43 GMT -5 jbjhillbilly said:

Interesting.

I feel like I have less control on curves at speed with ~30psi vs 35-40psi. Not arguing or advocating for higher pressures, just that the bike feels wobbly at 30mph around a sweeping curve if it’s at a lower pressure.

Or is that more to do with technique?

So many factors involed. My mechanic liked 40 on my KeeWay F-act.
He said it will improve gas millage.

Experiment with it, but I think beyond 40 would cause a blow out.

[aeroxbud]

Sept 5, 2021 16:32:39 GMT -5 collinsd84 said:

Sept 5, 2021 2:28:43 GMT -5 jbjhillbilly said:

Interesting.

I feel like I have less control on curves at speed with ~30psi vs 35-40psi. Not arguing or advocating for higher pressures, just that the bike feels wobbly at 30mph around a sweeping curve if it’s at a lower pressure.

Or is that more to do with technique?

So many factors involed. My mechanic liked 40 on my KeeWay F-act.
He said it will improve gas millage.

Experiment with it, but I think beyond 40 would cause a blow out.

It's interesting, tires are such a personal thing. I was reading a while ago that Harley Davidson fit different tires to their bikes for different markets. Here we like grip and not so worried about mileage. In the U.S. They fit rock hard tires as longevity of the tire is considered more important.

[collinsd84]

scooter7878 what r u riding? How many cc's?

[scooter7878]

Sept 6, 2021 10:17:53 GMT -5 collinsd84 said:

scooter7878 what r u riding? How many cc's?

139qmb 50mm with a stroker crank I guess it's somewhere about 89cc I'm not exactly sure but I run 38 to 40 psi I'm hitting between 57 and 60 mph on flats no wind the other night I actually hit 64 on a flat but that's rare. I do agree that tires maxed out like that affects grip but I run a soft tire compound and a wider tire I haven't had any traction issues

[collinsd84]

scooter7878 Thinking the wheel might need to b balanced.