Forum

[Rainmanshaun]

Hello to all! I have just bought a '98 350 Bullet Indian Export Chrome model.
My plan is to modify it into a trials type bike and need to get some trials type tyres.

My question is will a 4.00 - 19 tyre fit into the swinging arm? has anybody fitted one or do i keep trying to find a 3.50 - 19 tyre which seems a lot harder to come by?

[stinkwheel]

I think it's a firm "maybe". I'm reasonably convinced I wouldn't get one in my 350 bullet looking at how close the 3.50 x 19 comes but others claim to have squeezed one in there.

Heidnau K67 comes in 3.50x19

It does occurr to me that the size of the contact patch on a 3.50x19 is probably about the same size, maybe even bigger than the 4.00 x 18 they put on most classic trials bikes. I have a similar thing with the 29" tyres on my mountain bike, they look desperately skinny compared to the 26" standard ones but I actually have more rubber on the ground.

[Adrian]

The other option is to fit a swinging arm capable of taking a wheel with a wider tyre.

The good news is that our hosts sell one, part no. 92602 in the accessory catalogue.

The bad news is that it costs over £300 with VAT!

A.

[vince]

Hi, early redditch trials bullets were fitted with 4x19 tyres and didnt have widened swingarm. This was the standard size trials tyre of the period. Vince

[Wheaters]

The Heidenau tyre has its outer row of “knobbles” at an angle so the tyre is perhaps wider overall than the equivalent size old “trials universal” types.

Having used a 3.25 on rear of my bike (it was too wide for the front mudguard so I used it on the back wheel rather than try to send it back), I think a 3.50 would be the best option because a 4.00 might catch somewhere.

[Rainmanshaun]

Thanks for your replies - I have now removed the rear wheel and there is no way that the 4.00 - 19 is going to go in there. I have managed to source an Ensign 3.50 - 19 from the Classic Tyre Store so I will post on here if it fits....

[stinkwheel]

The Ensign 3.50 x 19 will fit fine.

[wr6133]

It does occurr to me that the size of the contact patch on a 3.50x19 is probably about the same size, maybe even bigger than the 4.00 x 18 they put on most classic trials bikes

I have a bike with 3.50x19 and one with 4.00x19. To look at you'd be hard pressed to tell the difference, try going up a muddy slope or giving it a handful while turning and you know which is the 4.00 though.

To make the 4.00 fit properly you need grind down the most forward mount for the chain guard, partially.

[stinkwheel]

Sure, but don't most classic trials bikes have a 4.00 x 18 rear? Which is what I was alluding to when comparing contact patch sizes.. Goes without saying that a 4.00 x 19 is going to have more grip than a 3.50x19.

[vince]

Hi, 4.00x 19 was the standard size for classic trials. 4.00 x 18 became the norm because the 19 tyres were no longer available. I have to fit an 18 rim and tyre to my AJS for that reason. Incidentally the chainguard forward mount is different on early bullets. Vince.