What size of innertube

[Boris]

The tube on the XR400 is loosing a few PSI a week and it's probably only going to get worse so I should have a spare to hand when I pull the tyre to investigate.

I see 18" tubes advertised as 4.10/3.50-18 the 18 bit is obvious but how do the other figures relate to the wheel width of 2.15?

Is the above 4.10/3.50-18 the correct tube?

[boboneleg]

The tube on the XR400 is loosing a few PSI a week and it's probably only going to get worse so I should have a spare to hand when I pull the tyre to investigate.

I see 18" tubes advertised as 4.10/3.50-18 the 18 bit is obvious but how do the other figures relate to the wheel width of 2.15?

Is the above 4.10/3.50-18 the correct tube?

4.10/3.50 is not really big enough for a XR400, what size tyre have you got on there Gordon?

I'd suggest in this range 120/90, 130/80, 140/80

Good info here............

http://www.michelinmotorcycle.com/pubs/fitment2012.pdf

[AlanH]

...and that'll translate to a 5.00/5.10 or thereabouts in old money based on my recent experience.

[Boris]

4.10/3.50 is not really big enough for a XR400, what size tyre have you got on there Gordon?

I'd suggest in this range 120/90, 130/80, 140/80

Good info here............

http://www.michelinmotorcycle.com/pubs/fitment2012.pdf

It's a 120 that on and I don't think I could go much wider without hitting something. The standard tyre size is a 110/100-18

Looking at the chart on the above pdf Michelin say for a 2.15 rim 110 is the max recommended tyre so it looks like I'm already slightly oversize.

Anyway the PDF shows the same tube for 100 - 130 section tyres (18 MFR TR4) which I gather is a 4.00 - 4.60

Now...

Anyone care to recommend a make (or one to avoid) and the cheapest place to buy.

[boboneleg]

It's a 120 that on and I don't think I could go much wider without hitting something. The standard tyre size is a 110/100-18

Looking at the chart on the above pdf Michelin say for a 2.15 rim 110 is the max recommended tyre so it looks like I'm already slightly oversize.

Anyway the PDF shows the same tube for 100 - 130 section tyres (18 MFR TR4) which I gather is a 4.00 - 4.60

Now...

Anyone care to recommend a make (or one to avoid) and the cheapest place to buy.

I've always found that you get what you pay for with tubes, buy an established brand.

Also Gordon a 110/100 enduro tyre (ie; Michelin AC10) is just as wide as a 120/90 trail tyre (ie: TKC80), it's very confusing.

Either of these tubes should be fine......

400/460-18 MICHELIN MOTORCYCLE INNER TUBE 110/9018 18MG | eBay

CONTINENTAL MOTORCYCLE INNER TUBE F18 4.00/4.25/4.50 | eBay

and then off course you have reinforced/heavy duty tubes.................

the list goes on