|
Post by Liteway on Jun 10, 2018 14:13:13 GMT -5
I wonder what criteria most are using to choose the size of wheels and tires on their trikes as this can have a large effect on handling/ride behavior.
When I converted my front end from ATV quad type to Can AM Spyder based, I weighed the replacement components and the bulk of the weight increase came from tires and wheels.
165/70 10s with a five inch rim width weighed 12 lbs. 165/55 14s with a five inch rim width weighed 24 lbs
I recently "upgraded" the wheels/tires on my VW Golf from stock, with the resulting weight increase as follows:
195/65 15s on a 6.5" rim weighed 36 lbs 215/50 17s on a 7.5 inch rim weighed 43 lbs
The change in wheel sizes on the trike was a big negative in the behavior of the front end resulting in less stability and much worse ride on bumpy roads, though there was no real difference on smooth payment. Too bad most pavement around here is not smooth. It's all about unsprung weight as a ratio to total weight, completely predictable.
If going from a 12 lb wheel tire assembly to a 24 is bad, I would imagine going to a 40 lb plus 17" wheel/tire could only have been much worse.
So, I am wondering how others on the site are fairing with their trike's when using tires and wheels designed to work with vehicles 4 times as heavy as their own.
BTW , the upgrade on the Golf had only minor effects of a slightly worse ride, slightly better handling. But man, it looks great!
|
|
|
Post by eclipse on Jun 12, 2018 2:37:44 GMT -5
Interesting question Liteway - keen to hear what others have to say on this. I suspect that oftentimes the decision will be made as a result of (a) tyre sizes and availability, and (b) aesthetics. In my case I originally sought 13" wheels which are proven on high-performance vehicles, but when modeled in I decided that, subjectively, they just look absurdly small in context of the rest of the vehicle! Thus, I'm finding myself gravitating towards 15"x7" wheel which gives me the benefit of a wide range of rim styles/sizes, a range of tyre widths and aspect ratios, and the look that I think works well. I'm slowly gravitating towards Caterham uprights for my first build as they offer a very cost effective plug-and-play means of getting a vehicle 'on the ground', which means that I'm tied to their wheel PCD and diameters. Hardly a limitation, though. In terms of ride and handling, it's also worth noting that the design of the wheel/tyre is critical in determining the inertia exclusive of the weight. If two wheels have identical weight but one has the majority of it's weight outbound (on the rim) and the other carries it's weight inbound (near the hub) then they will behave totally differently in use. This is relatively easy to assess, though, using a simple jig which supports the wheel in a horizontal plane with three equi-spaced lengths of string (as long as possible). If you rotate the wheel about it's axis by an amount (90 degrees or so) it will rotate and come to a stop, before rotating back the other way again. The frequency of these oscillations is indicative (~proportional) to the wheel's inertia value! Best regards, -Rob
|
|