spare wheel query
spare wheel query
Hi all, after viewing comments and pics of neglected space saver wheels I decided to check mine, looks ok. Then I noticed tyre size T125/90/R15. My wheels/tyre are 17inch. Local tyre place say it should be ok to use in case of puncture.Is he correct? Seems iffy to me. I would welcome your thoughts/comments. The wheels were on the zed when i bought it so previous owner ought to have known. Thanks.
- Southernboy
- Joined: Thu 07 Oct, 2010 12:39
- Posts: 6436
- Location: Johannesburg
Re: spare wheel query
It should be fine for 10-15 miles at low speed (35kph)...Question you must ask, are your tyres good enough to withstand everything short of a large nail or spike...most punctures are caused by large items if the tyre and tread are in better than 50% wear condition...the risk obviously increasing with wear. Also, when last did you have a puncture? I have been driving for 45 years, and I have yet to suffer the indignity. I do however maintain tyres at above 50% wear and change for new at that stage...I get a fair "trade-in" on my used tyres which offsets the new costs. There is a market for "used" tyres, so it's worth considering...even if it only ammounts to 20% - 25% of the cost of new rubber. Like buy 4 and get one free...
Re: spare wheel query
Hi
, I keep my tyres till around 50% worn.I have a trade account so its not so hard pricewise to renew them. I always buy top class branded tyres.I was just wondering about the space saver as a spare. Thanks for your input.
, I keep my tyres till around 50% worn.I have a trade account so its not so hard pricewise to renew them. I always buy top class branded tyres.I was just wondering about the space saver as a spare. Thanks for your input.
Re: spare wheel query
According to my handbook, the spare should be T115/90 R 16 92 M so it looks as though yours is an inch too small. It woud still get you out of trouble though in an emergency though.
I have had at least two occasions when a can of goo would not help, once a metal bar penetrated the tyre and on another occaasion I pcked up a nail or something which suddenly deflated on the motorway at ***Mph and by the time I managed to stop the tyre was shredded.
I have had at least two occasions when a can of goo would not help, once a metal bar penetrated the tyre and on another occaasion I pcked up a nail or something which suddenly deflated on the motorway at ***Mph and by the time I managed to stop the tyre was shredded.
Re: spare wheel query
Regarding the size - all wheels should have the same overall dimensions regardless of the rim size, as the profile of the tyre is adjusted to keep the rolling radius the same.
These are some common tyres sizes for the Z3:
125/90R15 = 2*(125 * 90%) + 15*25.4 = 606mm
225/50R16 = 2*(225 * 50%) + 16*25.4 = 631mm
225/45R17 = 2*(225 * 45%) + 17*25.4 = 634mm
255/40R17 = 2*(255 * 40%) + 17*25.4 = 636mm
225/40R18 = 2*(225 * 40%) + 18*25.4 = 637mm
From that, you can see that the spare is around 25mm smaller than the normal wheels, but as new tyres normally have around 7mm of tread (14mm if you count both sides) then the spare is not that much smaller than running one new and one bald tyre, and as it's only supposed to be used at no more than 50mph, it should not be a big problem.
Cheers R.
Edit: Just seen the post above - 115/90R16 would be 613mm. I have 125/90R15 on mine - it seems that manual for the later cars lists both 15 and 16 inch spares, but with different width tyres. You do have the correct size spare.
These are some common tyres sizes for the Z3:
125/90R15 = 2*(125 * 90%) + 15*25.4 = 606mm
225/50R16 = 2*(225 * 50%) + 16*25.4 = 631mm
225/45R17 = 2*(225 * 45%) + 17*25.4 = 634mm
255/40R17 = 2*(255 * 40%) + 17*25.4 = 636mm
225/40R18 = 2*(225 * 40%) + 18*25.4 = 637mm
From that, you can see that the spare is around 25mm smaller than the normal wheels, but as new tyres normally have around 7mm of tread (14mm if you count both sides) then the spare is not that much smaller than running one new and one bald tyre, and as it's only supposed to be used at no more than 50mph, it should not be a big problem.
Cheers R.
Edit: Just seen the post above - 115/90R16 would be 613mm. I have 125/90R15 on mine - it seems that manual for the later cars lists both 15 and 16 inch spares, but with different width tyres. You do have the correct size spare.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc