Too heavy for a 700c wheel?

[JohnD]

This is a about a pedelec but is more a general cycle question.

I have now been through 6 different inner tubes and two tyres - I cannot manage more than two return journeys without a rear flat!


I am 18 stone and riding a Dawes hybrid with a Sunlova kit that places the battery over the rear wheel - I have tried Presta and schrader (?) valves - slime filled tubes and both big apple and Marathon plus tyres - nothing worked.

My journey is only about 3 miles each way with a big hill in the way - there are a number of transitions from cycle path to road and back again - all by drop kerbs but still with a bit of a jar and crash.

So - am I simply too heavy for a 700c or is there something else?

Help

 

[NRG]

Some of the other members will know more than me on wheels and tyres but what type of punctures are you getting?

Is the inner-tube being pinched against the wheel rim?

What rim tape are you using? I recommend the Jante cloth tape

Whats the inflation pressure?

 

[fishingpaul]

I have a torq with 700c wheels and a marathon plus tyre on the rear,i weigh around the same as you and have had no problems, i do try and keep tyre pressures above 35 psi which could help,i would give the wheel rim a thorough check for anything that could be causing the punctures,even when i had around 12 kilos of lead acid batteries on the rear rack for six months, i had no punctures at all.

 

[John L]

That must be so frustrating!

I have the same kit on 700c wheels with marathon plus tyres. Best part of 2000 miles with no puncture. I'm a couple of stone lighter but carry a set of panniers on the carrier. So your set up should be well able for the weight.

I keep tyre pressure at above 100psi which is probably a bit high. As fishingpaul suggested check the rim for anything sharp including under the rim tape.

John

 

[Scimitar]

I'm the same weight at the moment, but was heavier when I started using the bike again and had no pinch flats from the rear crashing into potholes, etc. This is with a 26" wheel and the factory-supplied narrow cheapy tyre that came with the hub. I'd suspect some other cause, as suggested above.

 

[amigafan2003]

No, you're not too heavy.

Sounds like something is wrong with the wheel - check inside it for sharp edges and ensure you have high pressure rim tape - not the cheap rubber rubbish that comes with the majority of bikes.

 

[alexk-il]

What is the air pressure in your wheels?

I used to experience punctures due to a low pressure in the wheels. I'm currently doing fine with 60 PSI, but most of my experience colleagues at work keep telling me I need to get all the way up to 80psi to be on the safe side.

 

[oigoi]

When you get a puncture is it a pinch puncture (i.e. the inner tube is cut like it has a slit in it) or a spike puncture (the inner tube is pierced like a thorn or spike has gone into it?)
This will help determine the cause - if it is a slit then the inner tube is pinched, either by being trapped under the tyre bead or the inflation pressure being too low and the tube is pinched when you go over a big bump.
If it is a spike puncture there may be a thorn stuck in your tyre or perhaps a spoke is sticking through and piercing the tube

 

[Mussels]

You're not too heavy, something is wrong.
You haven't posted any tyre or rim widths, I'm guessing you aren't trying this on a 700x23 racing tyre - if you are then that's a good thing to change. Don't fiddle about with changing valves, just use the one the rim is designed for.
Your rim could be poor quality, the wheel could be poorly built, the tyres could be rubbish, the pressure could be too low, your rim tape could be weak or poorly fitting. Or it could be something else entirely.

 

[JohnD]

Thanks

OK good - thanks for the advice. I'm going to get professional assistance, have the wheel checked out and explore 'high pressure tape'

Thanks again

 

[Mussels]

OK good - thanks for the advice. I'm going to get professional assistance, have the wheel checked out and explore 'high pressure tape'

Thanks again

Better rim tape might be the answer if the punctures are on the inside of the inner tube, on the outside it won't make much difference. Can you describe where the holes are and what they look like?