Panniers, Punctures and Repairing Pneus

KneesUp

Guru
As I was merrily gurning into the icy wind on the way home yesterday I heard a tell-tale pffffft. Actually at first I thought a strap on my bag had come loose and was rubbing on the tyre, but no, it was one of those things we can't mention. I was only a mile from home, so I took the bag off the back and walked home.

On inspecting the inner tube on my return, the hole was quite obvious, and as it was already patchier than T-mobile's coverage I binned it - but not before lining it up with the tyre to see if I could locate a sharp thing.

What I found though, was this clover-leaf hole (on the left, below the reflective bit - I'm bending the sidewall)

IMG_20150128_172947_edit.jpg

I guess something has pinched it as there is a matching scuff on the wheel - the road I'd just been on is tremendously pot-holed and downhill, so I go quite fast - but in the dark I'm not quite as efficient at dodging the holes. I didn't feel any bump more severe than normal, but then it's always a bit of a teeth rattling section.

I've never had this sort of 'pinch flat' before, and this one has occurred only a few commutes into using my pannier rack; I've previously used a rucksack. Is this sort of thing more likely with panniers? On the bumpy roads I go down I generally come a little out of the saddle and absorb some of the shocks in my arms and legs. When I had the rucksack on this meant that my weight and the weight in the bag was sprung to a certain extent - that is to say it wasn't all rigidly fixed to the bike. Now I have the pannier there is about 5-6kg of 'stuff' rigidly attached to the bike over the back wheel (in one bag, on the opposite side to the hole) that I presume puts more stress on the tyre when I go through Sheffield's homage to the road surfaces of the blitz. Has anyone else noticed this sort of thing being more frequent with panniers, or is it just one of life's coincidences? The tyre was inflated to about 65psi by the way (according to my pump at least) - it's 26 x 1.5" and has a recommended range of 45psi to 95psi.

Finally - the tyre is almost new, and although I will pick up another tomorrow for not much, on an environmental level it seems wasteful to just throw this one away. Is there anything useful you can recommend I can do with it?
 

screenman

Legendary Member
I would go higher with the pressures. How healthy are you?
 
OP
KneesUp

KneesUp

Guru
I would go higher with the pressures. How healthy are you?
I run lower pressure than the maximum to get some comfort - at 95psi the bike was uncomfortable on the 'roads' I have to use. At 65psi the tyre 'drop' felt about right, although I never measured it, and the bike rolled really well. I suppose I might have got a slow puncture and not noticed - I didn't check the tyres before setting off if I'm honest, but the bike didn't feel any different - but it would explain it. At 65psi the tyres didn't look or feel soft.

Not sure what you mean by how healthy am I>
 

tournut

Active Member
Location
altrincham
As I was merrily gurning into the icy wind on the way home yesterday I heard a tell-tale pffffft. Actually at first I thought a strap on my bag had come loose and was rubbing on the tyre, but no, it was one of those things we can't mention. I was only a mile from home, so I took the bag off the back and walked home.

On inspecting the inner tube on my return, the hole was quite obvious, and as it was already patchier than T-mobile's coverage I binned it - but not before lining it up with the tyre to see if I could locate a sharp thing.

What I found though, was this clover-leaf hole (on the left, below the reflective bit - I'm bending the sidewall)

View attachment 78168

I guess something has pinched it as there is a matching scuff on the wheel - the road I'd just been on is tremendously pot-holed and downhill, so I go quite fast - but in the dark I'm not quite as efficient at dodging the holes. I didn't feel any bump more severe than normal, but then it's always a bit of a teeth rattling section.

I've never had this sort of 'pinch flat' before, and this one has occurred only a few commutes into using my pannier rack; I've previously used a rucksack. Is this sort of thing more likely with panniers? On the bumpy roads I go down I generally come a little out of the saddle and absorb some of the shocks in my arms and legs. When I had the rucksack on this meant that my weight and the weight in the bag was sprung to a certain extent - that is to say it wasn't all rigidly fixed to the bike. Now I have the pannier there is about 5-6kg of 'stuff' rigidly attached to the bike over the back wheel (in one bag, on the opposite side to the hole) that I presume puts more stress on the tyre when I go through Sheffield's homage to the road surfaces of the blitz. Has anyone else noticed this sort of thing being more frequent with panniers, or is it just one of life's coincidences? The tyre was inflated to about 65psi by the way (according to my pump at least) - it's 26 x 1.5" and has a recommended range of 45psi to 95psi.

Finally - the tyre is almost new, and although I will pick up another tomorrow for not much, on an environmental level it seems wasteful to just throw this one away. Is there anything useful you can recommend I can do with it?
Hi i would say 65psi is to low
As I was merrily gurning into the icy wind on the way home yesterday I heard a tell-tale pffffft. Actually at first I thought a strap on my bag had come loose and was rubbing on the tyre, but no, it was one of those things we can't mention. I was only a mile from home, so I took the bag off the back and walked home.

On inspecting the inner tube on my return, the hole was quite obvious, and as it was already patchier than T-mobile's coverage I binned it - but not before lining it up with the tyre to see if I could locate a sharp thing.

What I found though, was this clover-leaf hole (on the left, below the reflective bit - I'm bending the sidewall)

View attachment 78168

I guess something has pinched it as there is a matching scuff on the wheel - the road I'd just been on is tremendously pot-holed and downhill, so I go quite fast - but in the dark I'm not quite as efficient at dodging the holes. I didn't feel any bump more severe than normal, but then it's always a bit of a teeth rattling section.

I've never had this sort of 'pinch flat' before, and this one has occurred only a few commutes into using my pannier rack; I've previously used a rucksack. Is this sort of thing more likely with panniers? On the bumpy roads I go down I generally come a little out of the saddle and absorb some of the shocks in my arms and legs. When I had the rucksack on this meant that my weight and the weight in the bag was sprung to a certain extent - that is to say it wasn't all rigidly fixed to the bike. Now I have the pannier there is about 5-6kg of 'stuff' rigidly attached to the bike over the back wheel (in one bag, on the opposite side to the hole) that I presume puts more stress on the tyre when I go through Sheffield's homage to the road surfaces of the blitz. Has anyone else noticed this sort of thing being more frequent with panniers, or is it just one of life's coincidences? The tyre was inflated to about 65psi by the way (according to my pump at least) - it's 26 x 1.5" and has a recommended range of 45psi to 95psi.

Finally - the tyre is almost new, and although I will pick up another tomorrow for not much, on an environmental level it seems wasteful to just throw this one away. Is there anything useful you can recommend I can do with it?
Hi psi is to low put it to 80psi. As for pannier it should not be a problem. And best go the way to bye shwalbes marathon tyres, i have never had a puncture. Keep checking pressure weekly when winter is here. Good luck.
 

screenman

Legendary Member
Sorry that should have been heavy.

By going harder there is too a limit less chance of punctures, a snake bite is often but not always the sign of an under inflated tyre.
 

tournut

Active Member
Location
altrincham
Hi i would say 65psi is to low
Hi psi is to low put it to 80psi. As for pannier it should not be a problem. And best go the way to bye shwalbes marathon tyres, i have never had a puncture. Keep checking pressure weekly when winter is here. Good luck.
And have a look at the wheel rim.run your finger round it .
 
OP
KneesUp

KneesUp

Guru
Thanks for your replies.

Assuming the weight distribution of my weight and the weight of the bike is 65/35 rear front (it will be more equal than that, but we'll go with 65/35 as a worst case) it gives 63.5kg over the back wheel and 31.5kg on the front wheel. Add to the back wheel the 6.5kg of 'stuff' on the pannier (fat lock, pannier bag with laptop etc in it) and it works out at 70kg on the back and 31.5kg at the front. According to this article, for am optimum compromise between rolling resistance and comfort my back tyre should be 65 to 70psi. Given that my bike weight distribution is, I think, more equal that 65/35 (typical of a city bike) I reckon I was about right. Interestingly by the same chart my front tyre (also at 65psi) is way over inflated and should be more like 35psi.

That said, the article doesn't claim that the given pressures will be the most puncture resistant. I'll put the replacement up to 75psi (to give a margin for error) and check it more often. The more I think about it the more I suspect a slow puncture might have made the rear softer than I thought - it's a shame I can't be bothered fishing the inner tube out of the bin to check :smile:

I might also experiment with reducing the pressure in the front, but I think I'll rag the bathroom scales into the kitchen and work out what the weight distribution actually is first!
 
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