front tyre

[dumpy]

hi,could any one reconmend were to get a square section front tyre (side car)for my gs650 trike as been told that take a bit of the front shaking away,?

[rob]

hi,could any one reconmend were to get a square section front tyre (side car)for my gs650 trike as been told that take a bit of the front shaking away,?
shaking front tyre is an effect, not a cause, (if you see what i mean). changing the front tyre profile may, (or may not), mask the problem, but the cause lies elsewhere, incorrect steering geometry would be my first guess, though it could be any number of things, i would imagine front tyre profile to be fairly near the bottom of the list.....

[TektroG]

Most outfits running square section tyres are running 15" wheels and therefore use car tyres. Tyres on sidecars are often 13" (Watsonian)and are usually sold as trailer tyres.
I think Rob has a fair point, check other stuff first.

[johnr]

most sidecars run 10 inch mini wheels on the chairs, a lot of older outfits run 15 inch car tyres on the back as theyre the same as the old citroen 2cv car ones, and these days mercedes smart cars run wider low profile 15 inchers. however, whilst a square section is ok on the back and the chair, im not yoo sure about the front. as the action of steering tends to require the tyre to have some kind of rounded profile, i would stick with a bike tyre, they give better performance on the brakes too due to their softer profiles.
as has been said though, the shake is the symptom of the problem you have, a better way to be rid of it is to fit a steering damper, again this is masking the problem rather than curing it, but its a better option as some trikes and combos are inherently unstable due to their steering and suspension geometry.

[kiffer38]

my trike had a square section car tyre on the front, 190/55/15, and it wobbled its tits off, changed it, put a vmax rear tyre and wheel on the front 170/90/15 and hey presto wobble gone, so i reckon square tyre might not be the answer, as has been said, more likely something to do with the steering geometry rake/trail thats causing your prob !

[ratwing]

My theory - if you have a round profile tyre and 'bike-size' trail, the centre of the contact patch stays pretty much directly behind the point where the line through the headstock meets the ground when you steer. With wide square tyres and similar trail as you steer the centre of the contact patch moves sideways and forwards, I'm not sure why this results in a side-to-side wobble though.
I tried 15" car tyres on my Guzzi outfit and had slight wobbling, I pumped the front tyre up hard enough to make the tread bulge round instead of looking flat and the wobble (and straight line wandering) dissapeared. But, as the centre of the tread wore and the profile became flatter the wobble and wandering gradually came back.
So, unless theres something else causing it (like a bendy frame or worn bearings) you've got the choice of changing the geometry with a hacksaw and welder or changing the type of tyre I reckon.

[dumpy]

thanks guys