Experimenting with tyre sizes!

tt82 · Jun 7th, 2014, 13:10

So, ever since getting my V70 I've been looking at different tyre sizes, seeing if there is something which would help protect the alloys, give a better ride and possibly be cheaper. My standard size is 245/40R18 and other sizes I was considering were 255/40R18 and 245/45R18.

This week I ordered 2 of the latter and had them fitted today. Initially I had them fitted to the front to replace the worn out tyres. I was concerned that running 2 different sizes might affect the ABS and DSTC systems but on thinking about it, the spare wheel is considerably smaller than the main wheels and it is possible to run this without any issues. I can however report that there is no issue with the ABS or DSTC and on the way home, checking against my Sat Nav, 30mph on the speedo was 29mph on the Sat Nav and 40mph on the speedo was 39mph on the Sat Nav. So despite the increase in rolling circumference, the speedo reading is still under reading but is now more accurate.

I have now swapped the tyres round so the new larger size are on the rear and the worn originals are now on the front. As per my signature, I have started monitoring my fuel usage on Fuelly. I'm hoping to get a good average reading on Fuelly before the original size tyres on the front wear out, and put the new larger size on the front and I can then see if they have any impact on fuel usage!

On a slightly less technical note, the larger size does fill the arches more, giving a better look. They also do look like they will offer more protection against kerbing.

younger06 · Jun 9th, 2014, 23:02

My S80 came with 245/45/18 on it and if I only spent my time on motorways, I might be tempted to put 40 section tyres back on, but with the dodgy A and B roads that I spend a lot of time on, I think I will stick with the 45 section.

Going off topic, is your D5 the 185 or 205 model??

tt82 · Jun 10th, 2014, 07:44

Mine is the 185bhp single turbo D5.

Given how potholed the motorways are round here, I'll be sticking with 245/45R18 from now on. I had seen your post about your tyre sizes and as you've had no issues, I was definately going to go for it. The only question was whether I could get away with replacing 2 at a time or would I need to do all 4 in one go.

Jun 7th, 2014, 13:10	#1
tt82 Forum Support Team Last Online: Nov 28th, 2022 17:33 Join Date: Jan 2009 Location: Here.... obviously!	Experimenting with tyre sizes! So, ever since getting my V70 I've been looking at different tyre sizes, seeing if there is something which would help protect the alloys, give a better ride and possibly be cheaper. My standard size is 245/40R18 and other sizes I was considering were 255/40R18 and 245/45R18. This week I ordered 2 of the latter and had them fitted today. Initially I had them fitted to the front to replace the worn out tyres. I was concerned that running 2 different sizes might affect the ABS and DSTC systems but on thinking about it, the spare wheel is considerably smaller than the main wheels and it is possible to run this without any issues. I can however report that there is no issue with the ABS or DSTC and on the way home, checking against my Sat Nav, 30mph on the speedo was 29mph on the Sat Nav and 40mph on the speedo was 39mph on the Sat Nav. So despite the increase in rolling circumference, the speedo reading is still under reading but is now more accurate. I have now swapped the tyres round so the new larger size are on the rear and the worn originals are now on the front. As per my signature, I have started monitoring my fuel usage on Fuelly. I'm hoping to get a good average reading on Fuelly before the original size tyres on the front wear out, and put the new larger size on the front and I can then see if they have any impact on fuel usage! On a slightly less technical note, the larger size does fill the arches more, giving a better look. They also do look like they will offer more protection against kerbing. __________________ The more people I meet, the more I like my dog! 2009 V70 D5 R-Design - Jeade'en

Jun 9th, 2014, 23:02	#2
younger06 Volvo Newbie Last Online: Apr 19th, 2019 15:07 Join Date: Apr 2014 Location: Naas	My S80 came with 245/45/18 on it and if I only spent my time on motorways, I might be tempted to put 40 section tyres back on, but with the dodgy A and B roads that I spend a lot of time on, I think I will stick with the 45 section. Going off topic, is your D5 the 185 or 205 model?? __________________

Jun 10th, 2014, 07:44	#3
tt82 Forum Support Team Last Online: Nov 28th, 2022 17:33 Join Date: Jan 2009 Location: Here.... obviously!	Mine is the 185bhp single turbo D5. Given how potholed the motorways are round here, I'll be sticking with 245/45R18 from now on. I had seen your post about your tyre sizes and as you've had no issues, I was definately going to go for it. The only question was whether I could get away with replacing 2 at a time or would I need to do all 4 in one go. __________________ The more people I meet, the more I like my dog! 2009 V70 D5 R-Design - Jeade'en

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