gurrala74

Tyre upsizing !!

29 posts in this topic

After reading lot of topics here on tyres, I have following doubts

- Why there is a difference in tyre size of same car within its variant like Ritz LDI vs ZDI. Why the manufacturer does this

- Why people after taking the delivery of the car immediately change the tyres and rims or up size

- Is this kind or any kind of up sizing got an effect on car

I hope to receive experts comment on these things as I always think that such modifications are not good for any vehicle

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The manufacturers keep the cost down in lower spec models by giving lowspec tyres and wheels. In case of your car Maruti is saving you approx 1000/- per tyre and approx 3000/- per wheel. This reduces the cost of car by 20K compared to the Zxi/zdi models.

People upgrade tyres for better handling/comfort/looks without spending money on other luxuries of higher variant. It does not harm the car as you still are using the same specs as used by the manufacturer its higher variant!

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Tyres are of different size in same cars because it saves on cost. At times these tiny tyres look odd with alloys.

People change the tyre immediately because it fetches them a very good value on exchange. (I got 10k off on my new set of wheels on exchange of my existing tyres on my new car)

Up sizing of wheels helps in improving the handling of a vehicle and enhances road grip. Note : the overall circumference of the tyre should be maintained +-3% is acceptable

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@goenkakushal

Thank you verymuch for such good information. For example if I talk about my Ritz LDI which is the up sizing which suits in terms of everything more importantly not spoiling any of the OE fitment and also speedometer reading and if should not effect on engine or any thing which is related to the performance. I also request to tell me your reasoning for your selection and also benefits with that

Thanks in advance

regards

RK

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Basically the most OE tyres are puny and lack grip which the car needs with the amount of power in hand . Manufacturers do this so that the ARAI milege is good . Mostly a +1 upsize is the best when compared to the stock tyre sizes . There are some cars which provide adequate tyres only in top end varients like Punto (E+) ,Swift Z ,Ritz Z , 3series Exclusive etc . We should definately upsize the tyres after delivery on cars with terrible OE tyres like Swift ,Ritz ,Beat ,i10 etc because the amount of power provided by the car cannot be delivered on road due to poor quality tyres .

 

My i20 CRDi needs a +1 upsize for the power it has but the i20 P the stock tyres are more than fine .

 

Its not only about tyre width or size but a good quality tyres in a lower size will have more grip than a poor quality tyre in bigger size.

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If my Ritz LDI is with JK tornados and run for 13000km so far then what is the best suggestion for me now on tyres. If I feel road grip is not good, bumpy and tyre noise, then what should I look for future replacements about tyres

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Firstly go for a 195/60R14 tyres or 185/65R14 in your next tyre upsize with tyres like XM2 or ZLO . The Jk's are known to last for 40k + kms but I advise you to get them replaced after 25k + kms because as JK after sometime make too much noise especially on bad roads which can get irritating.

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@rssh

bro the tyre size mentioned by you will decrease the overall circumference considerably, hence not recommended.

 

 @gurrala

I will try to get some calculations for the best size.

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Radius:
12.19 in 309.62 mm Radius: 12.10 in 307.34 mm Radius: 12.23 in 310.64 mm Radius: 12.09 in 307.08 mm Radius: 11.99 in 304.54 mm Radius: 11.73 in 297.94 mm Radius: 11.60 in 294.64 mm
Circumference: 76.62 in 1946.1 mm Circumference: 76.05 in 1931.6 mm Circumference: 76.84 in 1951.7 mm Circumference: 75.99 in 1930.1 mm Circumference: 75.33 in 1913.3 mm Circumference: 73.70 in 1871.9 mm Circumference: 72.91 in 1851.9 mm
Revs per Mile: 852.8   Revs per Mile: 859.1   Revs per Mile: 850.3   Revs per Mile: 859.8   Revs per Mile: 867.3   Revs per Mile: 886.6   Revs per Mile: 896.1  
Actual Speed: 60 mph 100 km/h Speedometer1: 60.4 mph 100. km/h Speedometer1: 59.8 mph 99.7 km/h Speedometer1: 60.4 mph 100. km/h Speedometer1: 61.0 mph 101. km/h Speedometer1: 62.3 mph 103. km/h Speedometer1: 63.0 mph 105. km/h
Speedometer Difference: - Speedometer Difference: 0.738% too fast Speedometer Difference: 0.294% too slow Speedometer Difference: 0.820% too fast Speedometer Difference: 1.700% too fast Speedometer Difference: 3.963% too fast Speedometer Difference: 5.077% too fast
Diameter Difference: - Diameter Difference: 0.74% Diameter Difference: 0.29% Diameter Difference: 0.83% Diameter Difference: 1.69%

>
Diameter Difference: 3.82%

>
Diameter Difference: 4.84%

>
According to the above chart .. If you wish to upgrade to 15inch alloy then you can consider 195/60R15 , 185/65R15

If you wish to maintain current size rim and change only tyres then 185/70 R14 is the best choice

Note: Previous Zdi/Zxi models had 185/70R14 as OEM

New Zdi/Zxi models have 185/65R15 as OEM 

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@kushal

Very good information. Thank you

So if I maintain the same rim and change the tyre then it is 185/70R14. With six options here text is mixed up one into other. Can you please paste only the details of current stock tyre and the 185/70R14 for my clearing understanding the difference. So I should go for this change after I use these stock tyres till they get warn out.

Thanks once again

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185/70R14 is ideal as it is provided by Maruti in higher models

You can compare it with your current tyre

Radius:
12.19 in 309.62 mm Radius: 12.09 in 307.08 mm
Circumference: 76.62 in 1946.1 mm Circumference: 75.99 in 1930.1 mm
Revs per Mile: 852.8   Revs per Mile: 859.8  
Actual Speed: 60 mph 100 km/h Speedometer1: 60.4 mph 100. km/h
Speedometer Difference: - Speedometer Difference: 0.820% too fast
Diameter Difference: - Diameter Difference: 0.83%
>

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Radius:
  309.62 mm Radius:   307.08 mm
Circumference:   1946.1 mm Circumference:   1930.1 mm
Revs per Mile:     Revs per Mile:    
Actual Speed:   100 km/h Speedometer1:   100. km/h
Speedometer Difference: - Speedometer Difference: 0.820% too fast
Diameter Difference: - Diameter Difference: 0.83%
>185/70R14 is ideal as it is provided by Maruti in higher models

You can compare it with your current tyre

 

 

Sorry mods. You may pls delete previous post

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@kushal

Thank you, So there are slight differences here and there, will they effect in any form, if so please let me know

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You dont need to worry at all, there cannot be a better match than 185/70 R14 and the obvious reason this being OEM size .

Am personally using 195/60 R 15 on my Swift which was having same tyre as your Ritz.

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@gurrala

How much air do you keep in your wheels?

 

For tyres,

185/70 R14 Yoko A Drive is best VFM tyres and Michilin is slightly better but vastly costlier.

 

If your a sedate driver - Drive your Swift with the same tyre atleast another 15+k kms or till the tyres worn out.

 

For comfort, reduce air in your tyre. In my swift, 31 upfront and 30 behind is too good. (tyre - your spec'd Bridgestone)
creativebala2012-06-13 14:27:43

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I just changed my stocks in swift 2008 to MRF ZLo 185/70/R14. What shall be ideal tyre pressure in city drive with me as only occupant? In stock I maintained 32 throughout and it lasted 50k kms.

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@kushal

I have one doubt about the size 185/70R14. If the present Ritz Ldi is fitted with 165/80R14, then how 185 width will fit into 165 rim width ??

How does the 70 and 80 difference matter ??

I am just asking this for my information

Thanks in advance

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@gurrala

Yes you can fit 185 width or even 195 width on stock rim provided the Rim radius is same i.e. 14inch then the trye width can be changed in most cases, only if there is a big difference in the width size there may be an issue.

 

FYI

Assume the tyre size

185/ 70 R 14

 

Here 185 as you are aware is for width

 

70 is height of the sidewall of the tyre which is in terms of % of the width

hence 70% of 185 is 129.5mm

 

14 is offcourse the Rim size

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Opps I  assumed that the stock tyre was 165/70R14 .My bad !

@gurrala the following is the spec of a tyres rating

  185 (width)/ 65 (65%of 185mm)/R 14 (on 14inch rims)

  therefore 205/60R14 will have almost same diameter than the above tyres but tyre will be wider with same sidewall length.

 

Best is to get a good 15" alloy wheels and fit 195/65R15 or 205/60R15 tyres .

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@rssh

205 is a good option but in my view it will look a bit bulky on the car , however 205 on alloys will not look as bulky and rather enhance the look of ur vehicle.

Bro am sorry to interrupt again but 195/65r15 and 205/60 r 15 seems like a wrong size smiley1.gif

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Recently I filled them to 36/33 as given on the front door panel of my Ritz LDI.

This is where you made a wrong. Check correctly. Its 33 for 165 & 36 for 185.

So if your want better ride, simply reduce air.

185's Alloy width is atleast half inch wider than 165's rim.

If some one plans for Alloy, go for 15" and a softer compound Tyre, that increases the car's looks or stance by miles.

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I'm planning to give my swift new shoes smiley1.gif

My current stock JK Tornadoes have done 48k and are still good on the depth of the grip factor.. but as someone pointed out here, they make a LOT of noise.

Filtered down to Michelin XM1+ / XM2 whichever is available. Although, I see Yoko being talked about a lot. Can anyone share user reviews?

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@bala

36 for front tyre and 33 for rear as written on the side wall of the front door. now tell me what to be filled if the tyre size is 165/80/R14

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I think up sizing Tyre is doesn't matter and it has so many advantage like greater contact area with the ground, better control and handling.

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