Isetta wheels

[AndyL]

Posting this up here, as it seems to be a perennial subject.

I have a collection of Isetta wheels some in better shape than others. I think it's generally known that three wheel Isetta's had 3.5" rims at the back and either 3" or 3.5" rims up front depending on the age of the car, with pre '61 cars usually being fitted with the narrower wheels.

My car didn't have any front wheels when I got it, the drums were sitting in the dirt, I used a pair of old 3" rims I had to get back onto three wheels. I also picked up a couple of better condition 3.5" rims at shows many moons ago, however these have a slightly different rim style to the rear rims I have.

My plan was to fit 3.5" rims all round, as they're in better condition, and radials should fit better I think.

Does anyone know if this is correct, were there two different types of 3.5" rim on British Isetta's?

3" rim. Rough but serviceable with some work



Rear 3.5" rim. Good nick but not enough to go all round the car



Alternative 3.5" rim. I have a pair of these, and they're in much better condition than the 3" rims I have as you can see.
The main difference seems to be the outer part of the rim is deeper set than the rear 3.5" rim I have. Perhaps these were British made and the rear rim was German made?

[Barry]

I have just refurbished my rims.
Sand blast and stove enamel cream / ivory

My Isetta RHD was registered in August 1961

3" x 3 (inc spare)
3.5" on the back

I have no reason to suspect that anyone ever changed the rims.
The fronts (3") appear to be from thinner steel.
The back (3.5") appears thicker.

I would be concerned about fitting 3.5" on the front as clearances are fairly tight, especially with radials.
I have fitted - 145/80 x10 Falken Tyres (SN-807)  as suggested by Bob. 

[AndyL]

My car never had a spare- there were quite a few bits missing on my car that I had to source elsewhere.

I've always been led to believe that the spare should be a 3.5" as they were the only wheels that had enlarged stud holes that could fit on the back or the front.

Graham Dewhurst over on facebook says he runs his car on 3.5" rims all round with no issues.

[Barry]

If 3.5 rims work thats fine.  I just remember it being said that certain radials would not fit as they are too close to the suspension posts.  3.5" rims would not help, although, they are dished outwards.

My car had the back 3.5" wheel with a 5.20 crossply and the spare 3" with a 5.20 cross ply. looks like the stud holes in the spare have been increased in diameter.
It is hard to say what decisions the owners have been made over the years.......

Photo has a bit too much sun.  The wheels are cream / ivory not white

[Barry]

One of my front rims was balanced with weights on the inside.  That seems to be a No-No. on an Isetta.  The weight hits the suspension.

[Big Al]

If it was used on the trike rear, it would be the outside rim, as the wheel is back to front. Only a suggestion.

I think the spare wheel was an optional extra on an Isetta?

[Bob Purton]

You could just take the weight off as Isetta speeds will not present any problems with wheel wobbling.
I have no weights on my wheels at all.

[Barry]

Thats what I will do for now Bob.

Having experienced the wobble of death in the past I just wanted the wheels to be as smooth as possible.

[Barry]

Isetta is nearly ready for its MOT.
Last on the road in 1973/74  23,000 miles
I bought it in 1996.  How time flies.  About time it was dusted off.

[AndyL]

Wheel wobble or shimmer is caused by the single link steering, and worn silentblocs.

[Big Al]

Its caused by poor geometry, which is exasipated by single link steering and worn silent bloc bushings, I suggest. Trienkel has single link steering and silent bloc bushings, but does not suffer wobble until the bushings fail. Annoyingly the Treinkel suspension does not really work well, whereas the Isetta seems fine, within its design limitations. So neither car can claim the high ground. Back to best bits of each car thread Bob initiated.

[AndyL]

In truth I've not heard anyone moaning about shimmer on isetta steering if it's all in good order.

Woolly/disonnected steering is a complaint, but I think that is more due to the worm and nut steering box, whereas the Heinkel had a much more positive rack and pinion I believe. However might be thankful of the self locking nature of a worm if you were unlucky enough to suffer a blowout when cruising.

[Big Al]

Worm and pinion, so much better than maggot and peach from the days of optional steering. Or perhaps the Bond Mk A cheese cutter, too.