140/60/14 For The Rear

[haldunbilgi]

Hi to Everyone,
I've been using a 2016 PCX 150 for three months and planning to change the both tires.
For the front : 120/70/14 City Grip
For the rear : 140/60/14 City Grip

I've searched a lot but couldn't finf anyone using this combination. As I know both tires has 84 mm height.
Do I have to make any mod. if I use these tires? Or Will this change cause any technical problems such as handling or rubbing?
Thanks in advance.

P.S. I do not want to make any mods. but I really want wider and safer tires. Any suggestions?

[k2apache6.0]

I actually bought the fatty tires but instead a 140/70-14 for the rear. On seeing them for myself I had some misgivings, the distance between the tire beads was vastly wider than the rims they were going to fit. Several members had done the mod on the forum so I decided to go ahead, off to the tire fitter I went. On seeing them he adamantly refused to fit them, that was it for me, he basically reafirrmed my own thoughts. The sidewalls would be pinched in to a degree that the profile would be changed adding to the height and narrowing the look not to mention unwanted potential handling and safety issues. Add to that more unsprung weight, potentially more drag and altered gearing. Did I mention the mainstand? If you look at the pic of this modded bike both tires are on the ground, mathmatically there's only an 8mm increase in tire height between the stock rear and the 140/70, so what happened to the 25mm gap between the rear and the ground unless the profile had been changed due to pinching from a too narrow rim? I'm going with a 110/80 rear and a regular sized front city grip due to these observations.

[chicaboo]

so what happened to the 25mm gap between the rear and the ground

Having given this some thought now since our discussion:
The front tyre also got taller, which pivots the scoot backward about the centre stand.
So that means you're probably getting close to dropping 16mm closer to the deck at the rear.
I'm not sure a belted/reinforced tyre can balloon much (if at all) in diameter when properly inflated?
However, the sidewall will have an ideal rim width for its profile, and our rims are only 1.85" & 2.15" wide...

But yeah, I'm also somewhat over the excitement of real chubby tyres.
Although I would still like to go +20mm wide. But that rules out City Grips.

[k2apache6.0]

so what happened to the 25mm gap between the rear and the ground

Having given this some thought now since our discussion:
The front tyre also got taller, which pivots the scoot backward about the centre stand.
So that means you're probably getting close to dropping 16mm closer to the deck at the rear.
I'm not sure a belted/reinforced tyre can balloon much (if at all) in diameter when properly inflated?
However, the sidewall will have an ideal rim width for its profile, and our rims are only 1.85" & 2.15" wide...

But yeah, I'm also somewhat over the excitement of real chubby tyres.
Although I would still like to go +20mm wide. But that rules out City Grips.

Good point, yes. I even thought about using the 120 for a rear with a stock front, but that would have meant reversing the rotation, a non reinforced tire, and a lower profile still. I'm over the whole idea, canned.

[chicaboo]

You can get a nice size rear tyre in Pirelli Diablos for a premium price, but the guys here said they wear very fast.
The higher price, lack of availability and higher turnover on tyre replacement also ruled that out for me.

[haldunbilgi]

so what happened to the 25mm gap between the rear and the ground

Having given this some thought now since our discussion:
The front tyre also got taller, which pivots the scoot backward about the centre stand.
So that means you're probably getting close to dropping 16mm closer to the deck at the rear.
I'm not sure a belted/reinforced tyre can balloon much (if at all) in diameter when properly inflated?
However, the sidewall will have an ideal rim width for its profile, and our rims are only 1.85" & 2.15" wide...

But yeah, I'm also somewhat over the excitement of real chubby tyres.
Although I would still like to go +20mm wide. But that rules out City Grips.

Good point, yes. I even thought about using the 120 for a rear with a stock front, but that would have meant reversing the rotation, a non reinforced tire, and a lower profile still. I'm over the whole idea, canned.

First of all thanks so much for your valuable comments. And what about 140-60-14 rear? If I use 120-70-14 front and 140-60-14 rear will it cause any problems? What do you think? I think they have the same profile 84mm.

[k2apache6.0]

There's a video on here somewhere, you'll need spacers on the airbox and possibly the rear hugger fender. That's with the 140/70, so far as I know no one has done it with the 140/60

[haldunbilgi]

There's a video on here somewhere, you'll need spacers on the airbox and possibly the rear hugger fender. That's with the 140/70, so far as I know no one has done it with the 140/60

That's right, I have seen no one used the combination 140-60-14 for rear and 120-70-14 for front. Here I'm giving the calculation details for both tires.
Diameter inches (mm) 20.61 (523.6) 20.61 (523.6) 0 (0) 0%
Width inches (mm) 4.72 (120) 5.51 (140) 0.79 (20) 16.7%
Circum. inches (mm) 64.76 (1644.94) 64.76 (1644.94) 0 (0) 0%
Sidewall Height inches (mm) 3.31 (84) 3.31 (84) 0 (0) 0%
Revolutions per mile (km) 978.36 (607.92) 978.36 (607.92) 0 (0) 0%

All the detais seem appropriate . And What do you think? Also the original 100/90's diameter is 21.09 inches whereas the 140/60's is 20.61. Does it mean there won't be a rubbering problem?

[haldunbilgi]

so what happened to the 25mm gap between the rear and the ground

Having given this some thought now since our discussion:
The front tyre also got taller, which pivots the scoot backward about the centre stand.
So that means you're probably getting close to dropping 16mm closer to the deck at the rear.
I'm not sure a belted/reinforced tyre can balloon much (if at all) in diameter when properly inflated?
However, the sidewall will have an ideal rim width for its profile, and our rims are only 1.85" & 2.15" wide...

But yeah, I'm also somewhat over the excitement of real chubby tyres.
Although I would still like to go +20mm wide. But that rules out City Grips.

Thanks so much for the valuable comment.

[k2apache6.0]

There's a video on here somewhere, you'll need spacers on the airbox and possibly the rear hugger fender. That's with the 140/70, so far as I know no one has done it with the 140/60

That's right, I have seen no one used the combination 140-60-14 for rear and 120-70-14 for front. Here I'm giving the calculation details for both tires.
Diameter inches (mm) 20.61 (523.6) 20.61 (523.6) 0 (0) 0%
Width inches (mm) 4.72 (120) 5.51 (140) 0.79 (20) 16.7%
Circum. inches (mm) 64.76 (1644.94) 64.76 (1644.94) 0 (0) 0%
Sidewall Height inches (mm) 3.31 (84) 3.31 (84) 0 (0) 0%
Revolutions per mile (km) 978.36 (607.92) 978.36 (607.92)

All the detais seem appropriate . And What do you think? Also the original 100/90's diameter is 21.09 inches whereas the 140/60's is 20.61. Does it mean there won't be a rubbering problem?

Yeah' I've used the tire calculator too..but...It's not so simple as that, some may disagree but those figures don't take into account the sidewalls being pinched in on wide tires. We're talking of a difference of quite a lot between the tire's bead width the wheel's rim width here. When the wide tires are pinched in at the beads so as to fit, the profile is altered. The resting/unmounted tire looks wider than the mounted tire in the video. I know I have one sitting here right in front of me. Bottom line is these figures are only completely accurate when mounted on the correct sized wheel rim.You wont know until you try it, if it is so then your top speed will drop as a result of altering the final 'gearing' so no rubbing but less top speed if everything in the numbers is accurate once mounted.

[k2apache6.0]

Having looked at those calculations again it would seem that the diameter and circumference are the same so there would be no effect on the gearing, once again assuming pinching in the beads to fit the rims doesn't alter the profile which in my opinion it will.
I just measured the bead width on my 140/70 (outer to outer so as to fit inside the stock rim) it's 3.95", Rim width is 2.15". Now, when I pinch in the tire's beads to fit this rim size the shape of the tire is narrowed, the tread crown comes outward, and the outer tread starts to 'wrap' around to where the sidewall ought to be. That's the only way I can describe it. So in my op that is going to throw the calculations off.
On the front tire its just as bad regarding bead vs rim width, and one guy said the 'whiskers' on his new 120/70 were touching the fork sliders, another mentioned slight rubbing on the inside of the fender but couldn't be sure if the 120 was responsible for that or not.

[haldunbilgi]

Having looked at those calculations again it would seem that the diameter and circumference are the same so there would be no effect on the gearing, once again assuming pinching in the beads to fit the rims doesn't alter the profile which in my opinion it will.
I just measured the bead width on my 140/70 (outer to outer so as to fit inside the stock rim) it's 3.95", Rim width is 2.15". Now, when I pinch in the tire's beads to fit this rim size the shape of the tire is narrowed, the tread crown comes outward, and the outer tread starts to 'wrap' around to where the sidewall ought to be. That's the only way I can describe it. So in my op that is going to throw the calculations off.
On the front tire its just as bad regarding bead vs rim width, and one guy said the 'whiskers' on his new 120/70 were touching the fork sliders, another mentioned slight rubbing on the inside of the fender but couldn't be sure if the 120 was responsible for that or not.

Again thanks to you for all your detailed response. My mind is really mixed up And now I think the wider tires may cause potential problems. So it may be a good idea to use original size michelin city grip instead of IRC tires. Have a nice evening

[k2apache6.0]

Well in all fairness others have done the mod and are quite happy with it, I'm just giving the reasons why I didn't proceed myself despite having purchased the tires ahead of time. When my tire fitter guy parroted my own concerns, that was it for me. There is a 110/80 rear, I decided on that, though I have yet to have it and the stock size front city grip installed, there's still plenty of tread on the stockers after 3,150 miles so no need to rush.

[k2apache6.0]

Hmm here I go again, just seen Homies new video and I may revisit the idea and the 140/70. since I wont be using the 120 on the front the mainstand should keep the rear off the ground. I take it you watched the video's despite the fact the tires are 70 profile not 60? He has two on the forum, worth a look.

[dasshreddar]

OP 140/60 has not been done, but i'm sure you would like it.
I would assume the 60 series would not need the airbox "spaced"... or very little if so.
Or just use a pod filter...

[kramnala58]

OP 140/60 has not been done, but i'm sure you would like it.
I would assume the 60 series would not need the airbox "spaced"... or very little if so.
Or just use a pod filter...

Mine is a 2010 (Thailand) and I had not problem with the side clearance, although I put a pod filter on it at the same time.

I am not sure the 60 series will make a difference for airbox clearance, because, from my understanding (see cut/past below), the 140 signifies the width in millimeters, and the 60 signifies the height as a percentage of the width? Thus, the width would be 140 millimeters and the height would be 84 millimeters (60% of 140).

"Tire Width is the width of the tire measured in millimeters from sidewall to sidewall. The first three-digit number in the tire size refers to the tire width. For instance, in a size P215/65 R15 tire, the width is 215 millimeters. Aspect Ratio is the ratio of the height of the tire's cross-section to its width.

Here is a pic of what my pod filter looks like .... and as an added bonus, it adds a bit of a throaty sound to it.

DSCN2554.jpg (123.71 KiB) Viewed 3908 times

[k2apache6.0]

OP 140/60 has not been done, but i'm sure you would like it.
I would assume the 60 series would not need the airbox "spaced"... or very little if so.
Or just use a pod filter...

"Mine is a 2010 (Thailand) and I had not problem with the side clearance, although I put a pod filter on it at the same time".

I've been looking to get the Arashi filter pod myself without much luck.
Do you have a picture from of the tire from the rear, does the tire lose width once mounted to the narrow rim, it should still measure 140mm if it isn't being 'pinched' in?

[kramnala58]

OP 140/60 has not been done, but i'm sure you would like it.
I would assume the 60 series would not need the airbox "spaced"... or very little if so.
Or just use a pod filter...

"Mine is a 2010 (Thailand) and I had not problem with the side clearance, although I put a pod filter on it at the same time".

I've been looking to get the Arashi filter pod myself without much luck.
Do you have a picture from of the tire from the rear, does the tire lose width once mounted to the narrow rim, it should still measure 140mm if it isn't being 'pinched' in?

This is as good as I can do for a picture from the rear that I have on file. I can possibly get another one later. BTW .... it is a 140/70-14

Regarding the tire/tyre pinching in (losing width) when mounted on the OEM rim, I do not observe any loss of width, but don't have a pair of calipers to measure it accurately. But even if I could measure it accurately, I suppose to prove there was pinching, it would have to be measured when it is deflated, or better still, inflated, but on a wider non OEM rim.

If you would like a pic from directly behind, let me know and I will take one.

PCX Canister Breather 01.jpg (100.73 KiB) Viewed 3893 times

[k2apache6.0]

Thanks Kramnala, none of us are running non OEM wheels here so the point is to see if the pinching at the bead affects the tire's shape in any way, wider non OEM wheels wouldn't pinch. Off the bike the tire is exactly 140mm at is widest points. One other thing, does the mainstand still keep the rear wheel off the ground with the bigger tires fitted?

[kramnala58]

Thanks Kramnala, none of us are running non OEM wheels here so the point is to see if the pinching at the bead affects the tire's shape in any way, wider non OEM wheels wouldn't pinch. Off the bike the tire is exactly 140mm at is widest points. One other thing, does the mainstand still keep the rear wheel off the ground with the bigger tires fitted?

I am fairly confident that the bead was not pressed against the rim when mounted before inflating, which should indicate that there would be minimal to no pinching.

Regarding the center stand issue, there is still clearance of the rear wheel off the ground. I also mounted a 70 profile tire/tyre on the front, not the 60. Logically it would seem if a 60 were put on the front and a 70 on the back, clearance space would be less, but I think it would actually be the opposite because with a lower profile front, the bike would lean further forward, thus creating more space at the rear wheel. But I am prepared to be told that my thinking is all wrong about that.

Personally speaking, I have found the larger tires to be much better for handling, particularly when leaning the bike. As has been suggested above, maybe some of us are overthinking this.