Jump to content
Do Not Sell My Personal Information


Changing tyre size


Biomecanoid
 Share

Recommended Posts

Hello,


My car came with 175/65/R14 tyres can i go with bigger sidewall ? Like 185/65/R14.

As i understand things tyres are a part of the suspension so a bigger sidewall would give me a tiny bit more ground clearance and a softer more cushioned ride.

Is my assumption correct ? What more details would you need to make sure i can fit bigger tyres ? I have a 2006 Daihatsu Sirion


Thank you
 

Link to comment
Share on other sites


Need to check the effect on the speedometer - it is illegal to show a speed less than the true speed. There are a number of sites where you can input the tyre sizes of the original tyres and the proposed tyres, and the effect on the speedometer reading is calculated for you 

Link to comment
Share on other sites

The 185 figure refers to the width of the tread.  The 65 refers the the percentage the sidewall is in regards to the tread width.

Link to comment
Share on other sites

8 minutes ago, Stivino said:

The 185 figure refers to the width of the tread.  The 65 refers the the percentage the sidewall is in regards to the tread width.

I know so 185/65/R14 would be both taller and wider that 175/65/R14. So that's fine

Link to comment
Share on other sites

6 minutes ago, Biomecanoid said:

both taller and wider

Correct.

Link to comment
Share on other sites


1 hour ago, FROSTYBALLS said:

Need to check the effect on the speedometer - it is illegal to show a speed less than the true speed. There are a number of sites where you can input the tyre sizes of the original tyres and the proposed tyres, and the effect on the speedometer reading is calculated for you.

I went for an MOT like 2-3 months ago and they DIDN'T check that. They checked the fluids, the brakes, emissions, lights, and inspected the underside of the vehicle. So pretty basic stuff.

But despite what MOT does i try to keep my cars in top condition even if they are not supercars.

So the conclusion is that nobody cares or tests if the speedometer is off. So its OK to go bigger on tyres. 

The question remains Is my assumption correct that more side wall will cushion the ride.?

Link to comment
Share on other sites

I didn't imply that checking the speedometer reading was part of the MOT. 

Nonetheless, it is still illegal to have a speedometer that under-reads, and also it won't help you judge speed when approaching speed cameras, average speed cameras, etc, but it is your risk.

 

  • Like 1
Link to comment
Share on other sites

26 minutes ago, FROSTYBALLS said:

I didn't imply that checking the speedometer reading was part of the MOT. 

Nonetheless, it is still illegal to have a speedometer that under-reads, and also it won't help you judge speed when approaching speed cameras, average speed cameras, etc, but it is your risk.

The speedometer will be off by 1.7% which is negligible.  My question was more of a mechanical nature and not about legality which is just fine where i live.

Link to comment
Share on other sites

1 hour ago, Biomecanoid said:

The question remains Is my assumption correct that more side wall will cushion the ride.?

 I suppose that in theory, the answer will be yes.

But, I also suppose that tyres from different manufacturers will have different strength sidewalls.  So, the answer could be no.

🥴

 

 

 

Link to comment
Share on other sites

How much taller would a 185/65 be over a 175/65 ?      Is it worth the change?

Link to comment
Share on other sites

I make it 6.5 mm so nothing really as it’s only 3.25 more as it would be all the way round. I.e. measured at the top and the bottom as it were.  It’s only the difference between a new tyre and a worn tyre.

  • Like 1
Link to comment
Share on other sites

2 hours ago, Catlover said:

How much taller would a 185/65 be over a 175/65 ?      Is it worth the change?

Look here:

https://tiresize.com/tyre-size-calculator/

 

Size Diameter Width Wheel
165/65R14 -2.6%569 165 14 x 4.5-6"
185/60R14 -1.3%577 185 14 x 5-6.5"
205/55R14 -0.4%582 205 14 x 5.5-7.5"
225/50R14 -0.4%582 225 14"
175/65R14 Equal584 175 14 x 5-6"
195/60R14 +0.9%589 195 14 x 5.5-7"
185/65R14 +2.2%597 185 14 x 5-6.5"
175/70R14 +2.6%599 175 14 x 4.5-6"
205/60R14 +3.0%602 205 14 x 5.5-7.5"

 

 

Link to comment
Share on other sites

If there is a13” wheel that fits your car, and a tyre that would give an approx same outside diameter, then you would have a deeper side wall and potentially more “suspension”.

Link to comment
Share on other sites

3 minutes ago, Catlover said:

If there is a13” wheel that fits your car, and a tyre that would give an approx same outside diameter, then you would have a deeper side wall and potentially more “suspension”.

Yes you are absolutely right, but my wheels are just fine they don't need to be changed. On the other hand its about time to change my tyres so i am researching what are my options keeping my current original wheels.

Link to comment
Share on other sites


15 minutes ago, Biomecanoid said:

Yes you are absolutely right, but my wheels are just fine they don't need to be changed. On the other hand its about time to change my tyres so i am researching what are my options keeping my current original wheels.

Ah right, I thought your priority was for a softer ride.

Link to comment
Share on other sites

25 minutes ago, Catlover said:

Ah right, I thought your priority was for a softer ride.

Yes i would like a softer ride but nothing wrong with my current wheels. If they were damaged i would change them with 13'' steel ones. So what are my options while keeping my existing wheels ?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share





×
×
  • Create New...




Forums


News


Membership