Author Topic: Are scooters more prone to rear wheel slide than motorbikes?  (Read 563 times)

Thoppa

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Are scooters more prone to rear wheel slide than motorbikes?
« on: October 31, 2020, 12:16:16 AM »
Hi,

I've noticed my Citycom scooter is more prone to a rear loss of grip than the front. In fact, the front feels so unloaded it never feels anywhere near losing grip, but I can get the back to move around with some deliberately aggressive control. I wonder if this is true for scooters generally? It certainly feels quite different to a motorcycle in this regard.

I know it isn't the tyres - front and rear match so they have the same grip, and pressures are correct, both warmed up, running on the same surface (of course). It is, of course, harder to get the Pirelli Angel to slide compared to Maxxis but that's the coefficient of friction, nothing else. There's a discussion of why contact patch is largely irrelevant and it is weight that offers traction on this page https://www.stevemunden.com/friction.html

My Citycom seems typical for a scooter with a strong rear weight bias - 77kg front 107kg rear is roughly 40/60 distribution. So the rear should have more grip, yet it feels the opposite, with the front being more secure. Maybe it's the huge sprung weight of the engine assembly at the rear that has an effect?

Has anyone else had this experience? Is it a thing?

I've been riding for 30+ years - learned to do stoppies and get my knee down on sports 600s, wheelie and slide on a supermoto, so I find it hard to believe I'm imagining it.

The CC is my first scooter - just hit 70,000kms, 66,000 of which are my use, and she's still running well, although not as well as 40,000 ago. Top speed is much lower and fuel consumption is higher.
« Last Edit: October 31, 2020, 01:07:47 AM by Thoppa »
Ninja 650R
Citycom 300

Syd

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Re: Are scooters more prone to rear wheel slide than motorbikes?
« Reply #1 on: October 31, 2020, 05:36:08 PM »
I might have missed this: which tires are you using? The HD200's of old came stock with Duro tires ( Duro must mean Hard as a Rock in some language). When I finally replaced my Duros, they last forever too, my HD200 was a new scoot. Turned on a dime, planted in corners, Michelin City Grips.

Thoppa

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Re: Are scooters more prone to rear wheel slide than motorbikes?
« Reply #2 on: November 10, 2020, 07:41:49 PM »
Currently running Pirelli Angel.

The site I linked to does have some issues - he talks about hard static unpolished surfaces and equates them to soft dynamic polished ones, which is misleading, so his brick on steel analogy is inadequate.

These quora answers are much better https://www.quora.com/Why-do-tyres-with-larger-contact-surfaces-provide-more-grip-when-frictional-force-has-nothing-to-do-with-surface-area

I also read this research which says, "As inflation pressure increases, contact area decreases whilst wet grip increases." It sounds counter-intuitive but might explain why the smaller contact area of the front tire seems to have more grip in the wet than the wider rear.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjOmfnPuvrsAhUbM94KHXE0CggQFjABegQIAxAC&url=https%3A%2F%2Fpure.ulster.ac.uk%2Ffiles%2F11388459%2FMeasuring_grip_and_the_contact_patch_9780784413005.278.pdf&usg=AOvVaw1I_kxP_XjPL700tW7ljZtM
« Last Edit: November 11, 2020, 05:10:57 PM by Thoppa »
Ninja 650R
Citycom 300

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