Upgrading wheels/tyres on Santro

[rks]

Amazingly, I have managed to find the offset for the old Santro from the following website:

Autopure

Look at the specs for Hyundai Atos, which is essentially the old Santro. The quoted offset is 46 mm for the 4J X 13" steel rims, with PCD 114.3 mm and bore dia 67 mm.

As noted in the previous post, the offset for my alloys is 26 mm. I can console myself that the "backspacing" which is slightly greater than (half-rim-width+offset), and is equal to 103 mm for my alloy wheels, would be a close match to that of the stock steel rims of the Santro. Essentially what this means is that I am maintaining almost exactly the same distance of the wheel from the suspension parts, but since it is wider by 1 inch, it protrudes by almost that much ouside the wheel arch.

Let us see what happens this Friday when I push my car to 130+ kmph.

[autoenthusiast]

RKS, thanks for the reply.

If below is the case

I think the Xing stock rims are 4J. For 165/65, 4.5J is the minimum required as per the rim width calculator.

Then I guess something is wrong, since the carbibles site gives 4.5J even for 155/70. So either the manufacturer is giving the wrong size rims or the carbibles website rim size calculator is wrong or maybe we just have the Santro rim size wrong, and it actually is 4.5J

[rks]

Originally Posted by autoenthusiast

...Then I guess something is wrong, since the carbibles site gives 4.5J even for 155/70. So either the manufacturer is giving the wrong size rims or the carbibles website rim size calculator is wrong or maybe we just have the Santro rim size wrong, and it actually is 4.5J

The carbibles site may not be the tyre bible for Hyundai. I have seen another rim-width calculator that gives 4J as minimum width for 155/70, but still gives 4.5J for 165/65.

But note the following quote from the tyre bible at the carbibles website:

Oversizing tyres

If you want the fat look but don't want to go bonkers with new wheels, you can oversize the tyres on the rims usually by about 20mm (to be safe). So if your standard tyres are 185/60 R14s, you can oversize them to about 205mm. But make sure you recalculate the percentage value to keep the sidewall height the same.

So on this basis you are OK even if the Xing rims are 4J.

Anyway I personally don't think you need to upsize the tyres for the Santro. Even a wider rim (I now have 5J alloys) with the stock 155/70 tyres gives a greater contact patch and hence better grip. Plus the handling also improves. Pick-up has increased in my case, but I suspect that the top speed and mileage will come down. Will have to see how the decrease in offset affects the high-speed handling this Friday on the Expressway.

[autoenthusiast]

Folks a quick query, may look silly.

The carbibles site mentions the below for tyre runout stripes [

QUOTE]"The best thing is to have the coloured stripes on opposite sides of the tyres for opposite sides of the car, so that the runout on each side will counteract the other and help maintain a good straight running."[/quote]

When I installed my Bridgestone Turanza's the Bridgestone dealership mentioned that the runout stripes are placed on the innerside for all the wheel's and not on the outerside.

Any opinions ? Thanks.

[autoenthusiast]

Folks had written to Chris Longhurst, the author of the carbibles website. Below are the emails.

__________________________________________________ _________

Hello Chris,

First of all let me thank you for your excellent articles. They are the best I have come across till date and your website has a huge fanclub following on most of the forums that I am part of.

I had a query on the section for the runout lines on tyres, you mentioned "Quote - The best thing is to have the coloured stripes on opposite sides of the tyres for opposite sides of the car, so that the runout on each side will counteract the other and help maintain a good straight running."

Do the runout lines only have to be on the outer side ? or can they all be on the inner side of the car ?

Thanks Chris.

Kind regards,

(Name deleted)

__________________________________________________ _________

Response below:

(Name deleted) - no they can be on the inner side too. As long as they're not both to the left or both to the right, they'll somewhat counteract each other.
Chris.

__________________________________________________ _________

[rks]

Originally Posted by rks

Neo's official website is:

Neo Wheels India

From this website, the details of the alloy that I have purchased are available:

****************************************
Alloy name ------Star SM (lhere SM=silver-machined)
Size-------------5J X 13"
PCD-------------114.3 mm
Backspacing-----103 mm (what is this?)
Offset-----------26 mm
Bore Dia ---------Min. 58.4 mm-----Max. 70 mm
****************************************

There is only one more alloy from Neo that would have been suitable for my Santro, namely Breeze SM, with offset=36 mm and Backspacing=116 mm. and other specs same as above. This alloy would not have protruded so much and probably would have permitted upsized tyres.

In fact the Breeze model has been discontinued by Neo. Between Aura and Neo, the above Neo model (Star SM) is the only one available in PCD 114.3 mm and in size 13" X 5J; there are no alloy wheels below 5J with either Aura or Neo. Pretty dismal scene. I called the Aura dealer in Mahim, Mumbai, and he said that there are some imported models (League, etc.) available in PCD 114.3 mm that may be suitable for the old Santro. I doubt if these would be in size 5J X 13", though. If any T-BHPian has fitted alloys for the old Santro, please do post your experience.

[autoenthusiast]

Folks, I replaced the tyres on my Santro Xing today.

Put Bridgestone Turanza 165/65R13 on the stock steel rims.

am driving across to Mumbai on the expressway this weekend, shall let you all know about my experience with the new rubber.

Folks, did a Mumbai-Pune-Mumbai trip today, the new 165/65 Turanza tubeless tyres are really amazing.

Below are the immediate benefits/improvements that I found.

1. Vehicle handling has dramatically improved. Compared to the stock Santro 155/70 stock tubetype tyres which used to feel real unsafe whilst taking sharp turns at high speeds, the Turanza's are amazing and really allow for high speed cornering.

2. Another drastic improvement that I noticed was for the tyre noise, this too has significantly reduced.

3. Tyres do not heat up much after high speed driving.

4. Comfort has taken a total turnaround, the soft rubber/tyres really make the ride much smoother.

All in all, I wish I had changed my tyres earlier, it was 38,000km on the stock tyres before I moved to these new tyres.

[rks]

Originally Posted by rks

Neo's official website is:

Neo Wheels India

From this website, the details of the alloy that I have purchased are available:

****************************************
Alloy name ------Star SM (lhere SM=silver-machined)
Size-------------5J X 13"
PCD-------------114.3 mm
Backspacing-----103 mm (what is this?)
Offset-----------26 mm
Bore Dia ---------Min. 58.4 mm-----Max. 70 mm
****************************************

Here is an update on my recent Pune-Mumbai-Pune trip. Friday evening I set off to Mumbai as usual. Unfortunately I could not set the tyre pressures accurately on the forward trip because my digital pressure gauge battery failed.

I hit a top speed of 152-153 kmph on a sloping stretch while approaching the end of the Lonawala ghat section. I think top speed has come down by about 2 kmph, but this could be due to other factors. On the forward trip I felt that the high-speed handling had come down a notch as I thought that the car weaved about a little at 130+ kmph. But I believe this was more due to inaccurately set tyre pressures (probably a variation of 2 psi between tyres, i.e., at about 32-34 psi cold) and exceptionally heavy winds in the initial 10 kms upto the inlet toll gate.

On the return trip this morning I set all the tyre pressures accurately to 35 psi cold using my digital gauge (cell replaced). The car was now rock steady even at top speed, again 152 kmph on the sloping stretch after the second Kamshet tunnel.

The alloys are truly outstanding. Definite improvement in pick-up, no noticeable change in fuel economy (about 12 kms per lit), probably a very small drop in top speed, 2-3 kmph, due to the wider contact patch with the wider wheels (now 5" as compared to stock 4"). The cornering has improved tremendously due to two reasons -- a wider contact patch (less flexing of sidewalls) and also the wider stance of the car -- remember that my alloy wheels protrude out by about 33 mm as compared to the stock wheels. The improvement in cornering was very noticeable in the Lonawala ghat section. There is really no need to upsize the tyres, which is not possible anyway with these alloys due to the fouling problem. I plan to go for more grippy high-speed tyres, like the Turanza ER-60, when my present S322 tubeless tyres wear out. This should be much more than enough for my Santro. The braking has also improved noticeably, probably due to the wider contact patch -- it should improve still further with better tyres.

The car's handling over bumpy roads has improved noticeably due to the wider wheels. In particular, there is a speed-breaker with a series of small bumps exactly at a corner near the end of a bridge approaching the Lonawala ghat section from Pune. My stock rear wheels always threaten to slide over these bumps if I either brake or go too fast, since I am also cornering at the same time. But this time the car went smoothly over these bumps as I took the corner. In general the car seems to take potholes much better than before.

From internet discussions, I gather that the wider stance of the car (wheels jutting out from the wheel arch) will stress the wheel bearings because my alloys have an offset that is 20 mm less than the stock figure of 46 mm. So it remains to be seen if the Hyundai wheel bearings have enough over-design to take the additional stresses. Otherwise I can expect the bearing life to come down.

I thought the steering and handling of the car with the alloys was outstanding, despite the significant drop in offset. I wouldn't say that the steering was significantly superior with the stock wheels, even at 140+ kmph -- perhaps only an expert can make out any difference at all. I would say that up to 120 kmph, there is no question that the alloys give a noticeably superior handling to the stock 4" steel wheels.

Overall I would strongly recommend these alloys for the old Santro, if one is willing to take off the front mud flaps (to avoid a fouling problem at almost full turn) and provided the wheel bearings hold up. Will have to wait 5-6 months to see if there is any significant reduction in the life of the wheel bearings. It is vital that these alloys are an exact match in terms of PCD and Bore Diameter. There were absolutely no vibrations of any sort at full speed, either in the steering or in the wheels.

[rks]

There is one point I want to add regarding pick-up. I thought the pick-up of my Santro improved noticeably in third and fourth gears with the alloys, as compared to the stock steel rims (I never gun my car in first/second gears, so I couldn't comment on these).

But in fifth gear, the pickup is good at lower speeds, but the car seems to run out of steam while going uphill at high speeds a little earlier than with the stock wheels. E.g. on the long upward slope while approaching the first Kamshet tunnel on the Expressway (Pune to Mumbai) the car used to slow down from 130-140 kmph to about 100-110 kmph in fifth gear with my stock 4" steel rims. But with the 5" alloys, the car slowed down to 90 kmph in fifth gear on the same slope. Of course this varies a great deal depending on wind conditions, fuel quality, etc.-- so I need to test this a little more.

On the other hand, the fourth gear performance seems to have improved and the car is willing to hit 130 kmph in fourth even while going up mild slopes. So if I want to maintain high speed uphill, I need to change to fourth a little earlier with the alloys. This, I think, is to be expected, since the wider contact patch would provide greater rolling friction and in fifth my Santro probably does not have enough torque to overcome this additional resistance while going uphill at high speed. Here is where performance modifications (K&N filter, free flow exhaust) can help.

[rks]

Originally Posted by autoenthusiast

Folks, did a Mumbai-Pune-Mumbai trip today, the new 165/65 Turanza tubeless tyres are really amazing.

Below are the immediate benefits/improvements that I found.

1. Vehicle handling has dramatically improved. Compared to the stock Santro 155/70 stock tubetype tyres which used to feel real unsafe whilst taking sharp turns at high speeds, the Turanza's are amazing and really allow for high speed cornering.

That is to be expected when you shift from tubed to tubeless tyres. The tubed tyres will naturally have more sidewall deformation under hard cornering and grip/handling will be affected. You will see a significant improvement with tubeless 155/70 tyres also.

2. Another drastic improvement that I noticed was for the tyre noise, this too has significantly reduced.

To be expected when you go from tubetype to tubeless. It is also a function of the tyre pressures you maintain (Low pressures -> More noise) Not necessarily due to upsizing.

3. Tyres do not heat up much after high speed driving.

How fast? For how long? At what pressures? All of these count. Anyway most of the modern tyres that have an adequate speed rating will handle high speeds without overheating if they are at the correct pressure. Bridgestone advises to over-inflate tyres by 5 psi for high-speed driving mainly to avoid heat build-up and excessive sidewall flexing.

4. Comfort has taken a total turnaround, the soft rubber/tyres really make the ride much smoother.

The softness of the rubber also makes the tyre grippier. But be advised that on bad roads in Pune/Mumbai in the monsoon season, this *may* work against you when you hit potholes or stones hard. Then you may end up with tears or sidewall damage and wish that you had the old, reliable, hard, noisy S322 tyres.

Of course it is quite possible that 165/65 is a more appropriate upgrade for the Xing, considering that it has more power to handle the higher grip (and higher rolling resistance). As you can see from my post, the fifth gear performance for my old 1-lit Santro will probably come down significantly at higher speeds if I fit 165/65 tyres, as compared to the present 155/70 (tubeless).

[vid6639]

hey autoenthusiast dont worry about any tears or sidewall damage. The turanzas available in india have a reinforced sidewall as well as a sidewall protector. They are very suitable for indian roads.

If you take another tyre like the S322 or the Potenza G-III of the same size you will notice that the turanzas look fatter. this is due to the reinforced sidewall.

The potenzas are softer offering more grip and better performance. The S322 may last longer but are budget tyres and are noisy and hard.

Also the turanzas do offer a quieter ride.

I have the turanzas as well on my lancer and even after some offroading they are still going good. Although I'm not happy with the grip compared to the Potenza or Michelins I dont mind it since they are quieter.

[autoenthusiast]

Thanks vid6639, actually am pretty happy for going for the 165/65 Turanza's.

Feel it was the best thing I could have done and have no regrets about any other choice.

And yes you are right, the S322 was very noisy, high speeds on the expressway used to be a real bother since the tyre noise used to really intrude into the cabin. The Turanzas are extremely silent compared to the older tyres. A boon if you ask me.

As for the grip compared to the Potenza or the Michellins, honestly don't know the difference since I never tried the latter.

Thanks once again.

[rks]

@autoenthusiast: I am also toying with the idea of trying out the Turanza when my present S322's wear out. But I believe Bridgestone is coming out with a new tyre (B250 series; see T-BHP thread) that will replace the S322. I might go for that instead of Turanza.

I drove to office today in an unusually sedate mood. I was testing the minimum gear shift speeds of my Santro after fitting the alloys. Here are my observations, with AC on and tyre pressures at 35 psi:

Gear shift--------------Min. speed (5" alloys)--------Min. speed (4" stock)
1st to 2nd--------------~5 kmph---------------------~10 kmph
2nd to 3rd-------------- < 15 kmph--------------------~20 kmph
3rd to 4th---------------~20-25 kmph---------------------~35-40 kmph
4th to 5th---------------40-45 kmph-------------------45-50 kmph

In short there is an excellent improvement. I am especially happy that the car does not stall anymore at slow speeds (~10 kmph) in second gear, forcing an awkward shift to first. Secondly the third and fourth gear performances have improved beautifully; so I need fewer gear changes in city. There is no doubt that city driving is now even easier and probably with better fuel economy.

In fifth gear the pick up is probably better than before as you increase speeds from about 45 kmph up to a certain figure (100 kmph?). After that my feeling is that the stock 4" wheels peform better. I noticed that the fifth gear top speeds throughout my drive on the Mumbai-Pune Expressway were a touch lower than before (~ 5 kmph?). But this variation happens even with my stock wheels, may be due to fuel quality, winds, etc. So I need to test 5th gear peformance at high speeds a little more.

There is no doubt though, that the top speed in 4th (and probably 3rd as well) has increased. As I noted, I could hit 130 kmph (and still increasing) on an upward slope in 4th whereas this was a struggle earlier. But I am reluctant to push the car too much in 3rd/4th because I do not want to red-line the car, given that there is no tachometer in my Santro.

[rks]

Originally Posted by rks

I was testing the minimum gear shift speeds of my Santro after fitting the alloys. Here are my observations, with AC on and tyre pressures at 35 psi:

Gear shift--------------Min. speed (5" alloys)--------Min. speed (4" stock)
1st to 2nd--------------~5 kmph---------------------~10 kmph
2nd to 3rd-------------- < 15 kmph--------------------~20 kmph
3rd to 4th---------------~20-25 kmph---------------------~35-40 kmph
4th to 5th---------------40-45 kmph-------------------45-50 kmph

Sorry, I think I messed up. Here is the correct table:

Gear shift--------------Min. speed (5" alloys)--------Min. speed (4" stock)
1st to 2nd--------------~5 kmph---------------------~10 kmph
2nd to 3rd-------------- ~ 20 kmph--------------------~30 kmph
3rd to 4th---------------~ 30 kmph---------------------~35-40 kmph
4th to 5th---------------40-45 kmph-------------------45-50 kmph

[autoenthusiast]

@RKS, so overall you feel that putting the wider 4.5J rims has helped in incrasing stability ? If that's the case maybe I too may consider in upgrading the wheels on my Xing. Not sure of the impact on the tyres though, after using them on 4J and then later shifting to 4.5J, what are your opinions ?

Also you mentioned earlier that Birdgestone recommends to use approx 3 - 4 PSI more for high speed driving, never came across that reference on the bridgestone site, can you give me the link for the same. Thanks.