Adventure Bike Rider

Afternoon

While mooching round the interweb looking for tyres i came across Heavy Duty inner tubes (4mm i think). My ten has a 17" rear though and they only seem to come in 21" and 18".

I did read somewhere of people using an 18" HD tube on a 17" rim but just wondered what you guys think?? Think im gonna get one for the front,(about £25) but not sure what to do about the rear...any thoughts?

i used to do a lot of mountain biking and i hate punctures, and on a motorbike there even worse so HD inner tubes sound appealing.

Just need to decide Mich T63 or a MT21 front now...then buy new handguards, fit my bar risers, get a tail pack & spend lots more money and time i dont have

Cheers

Well I have never used HD inner tubes, and have done quite a lot of LDT's . Not had a problem with punctures on standard tubes at 6psi....... (Get new tyres before they get to the limit).

However if you use a tube bigger, either in width or diameter, than the wheel, you are then in Pinch Puncture land.... Well in, if you have to run on lower pressures.... And Thicker tubes wont help....


Going away from Bikes... The Class 8 Car Trialists use Tubes a diameter or width Smaller than the wheel to avoid Pinch Punctures when running on low pressures....

Hope this helps your decision.....

A lot of people (myself included) carry a 21" spare tube on the basis it can be fitted in either wheel BUT it is only a "get you home measure" as increased friction between the tyre and tube may cause it to puncture.

HD tubes are often marked "not for highway use" but I think this is just for the US market, I have been using them on the CCM for ages with no problems, including a few 100 mile round trips on the road at 15psi

I run HD in the 21-in front and Michelin Airstop in the 17-in rear.

I don't know how many people have successfully used a 21-in tube in a 17-in tyre, but when I tried it in an emergency the tube exploded dramatically 40km down the road. So I won't be trying that again!

IMO medium duty are fine, much easier to fit and if you pick up a nail or fencing staple and it goes through the tyre it's not going to make any difference if you've got a 2mm or 4mm inner tube. Hight be handy on a trials bike when you're running less than 5psi in the tyres. if you're tavelling light a spare 21" tube will get you home.

Mad Cow wrote:


Whys that? Is it due to sustained heat due to high speeds? Ive found some 17" HD tubes but there advertised as "motorcross".

Because they're thicker the constant flexing builds up more heat than thinner tubes especially if you are running lower pressures on the road as well. They do provide better rock impact protection when travelling at speed with reduced pressures.

The problem comes when you run at high speed on the road, especially at low pressure. Riding through Spain I kept around 100kph for most of the time.

Also, I don't lower the tyre pressure as the trails I ride in Spain and Morocco are never consistently sandy or muddy, and the moment you are onto rocks or stones you are in danger of snake bite punctures.

The lowest psi I'll dare run even with UHD tubes is about 20-21 in the front with 17-20 in the rear. The rear isn't so bad but I have no rim locks at present so don't want to risk ripping the valve out. If you're going be more brutal, then time for some mouses (spelling?)

I run 4mm HD tubes and have 16 psi front and 20 psi rear. Never had a puncture in 4 years of trail riding or a recent two week trail ride in Croatia covering 1800 miles

well, ive ordered a HD michelin tube for the front (90/90 -21).

Have seen somne 17" tubes but mine is a 130/80 and they seem to be 100/70. Some also seem to list small numbers like 17" - 4.50 (i dont know what these means )

The 4.50 is the width in inches. I'm running 130 tyres on a 4.5" rim so would have thought 4.5" tube should be ok.

Dysan wrote:


I've got a bloody great tub of mousse lube I use it with the heavy duty tubes fitted to my road bike though it probably doesn't make any difference but it's not a big job to take tyres off and lube the tubes so I do it anyway.