Spartamet Blowing off Schwalbe Marathon 42 x 590 tyres.

[Mopeder]

Hi,
Just joined the forum and I'd like to ask if anyone has had any problems with tyres on the special alloy rear wheel of Spartamet/Saxonette motorised bikes.

It is marked 24 x 590 and when I bought the bike it had a cheapo 37 x 590 tyre, which I changed for a Schwalbe Marathon 42 x 590 puncture resistant tyre (and one on the front too).

I then went for a 3 mile ride, and just after I got off, the rear tube exploded with a tremendous bang. I thought that was a fault in the tube, but on my next ride the tyre came off the rim without the tube exploding.

I'd checked before buying the Schwalbes, and they were recommended as the best type and size for the Spartamet.

Funny thing though, they go on the wheel quite easily, without even needing tyre levers. Other people have said they're normally really tough to get on, because of the reinforcement.

I've tried two, so I can't see it being a faulty tyre.

I've reverted back to the original 37 x 590, and they stay on fine, and need levers to get them over the rim.

Here's a photo of the cross section of the rim, together with the markings on the tyres. As you can see, they're all clearly marked as "590", so I'm mystified.

Any one had any similar problems with bike tyres ?

 

[grinningremlin]

Sounds like improper fit or too much pressure, marathons are a low pressure tire 50 bar max.Maybe contact Schwalbe.

 

[Mopeder]

Thanks for the reply and suggestion.

The Schwalbe is marked on the rim as 3.8n bar 55psi max, and the Spartamet manual specifies 3.8 bar for the rear tyre, so I had always inflated it to 55psi, 3.8 bar. So I don't think it can be over pressure.

I've tried two of them, so I don't think it's a tyre fault.

I'm still mystified why it's so easy to get the tyre beads over the rim, even without tyre levers, when I thought that Schwalbe Marathons were notoriously tight to get on ?

By comparison the cheapo 37 x 590 previous tyres are much tighter to fit, and they don't have any sort of puncture proofing, so are lighter and more flexible.

 

[grinningremlin]

I'm guessing improper fit, should be tight, but I've never need irons for my schwalbes.Also looking at the pic of your rim, I notice the wall is smooth, where the bike rim has a little lip for the bead to set in.I'm thinking you need moped specific tires, shot in the dark, I've never dealt with mopeds.

 

[Mopeder]

Yes, that is certainly a difference with the Spartamet alloy rim. All of my other bikes, (motorised and not) do have the lip, rather than a straight side.

Funny thing though, although here in the UK the Spartamet is licensed as a moped, it is much more like a normal pushbike, and the manufacturer never specified anything other than normal bike tyres.

Another of my motorised bikes is a Bernardi, and that has a conventional bike rear wheel, becuase the engine is on a roller drive, slung underneath. That uses ordinary bike tyres too, and they're both 35cc, two stroke.

 

[grinningremlin]

I REALLY like that Spartamet!They both look like MAB's to me.How does the motor drive the back wheel on your ride?

 

[Mopeder]

It has internal gearing direct from the engine in the centre, just one ratio, with an auto clutch, and a freewheel so that it can be pedalled independently.

The chain and crankset is single speed, quite a high ratio, aimed I think at being able to "help" the engine on steep hills at around 15mph.