Bigger tire questions answered

[Mgalutia88]

A short list of things I thought of for refference to our bikes.
I am excluding the stock size knowing better than Honda part here because we do need to keep in mind that the bike was designed for fuel efficiency including the factory installation of "low rolling resistance" tires. ie Toyata Prius

1. Do larger tires fit? - Yes, with 4-5 washers and longer bolts spacing out the airbox and the inner fender removed. (A new fender is $6.00 from the local dealer here.)

2. Do larger tires affect ride? - Yes, the ride is less harsh and the "bigger is better" placebo definetly helps. Also stability is increased from the larger rotating mass so highway riding is more enjoyable.

3. Will I loose performance - Yes. 2-3 miles per gallon. Also the speedometer will be off by several mph. Acceleration is ever so slightly hindered. Top speed will be reduced by SEVERAL mph because of the larger mass being moved.

I would definetly suggest larger tires to those with bore kits installed.

[Reaper]

What tire size do you use? on OE rims? R13 rims for the PCX is see for sale are all bad looking, imho.

[Mgalutia88]

I'm running a 120/70-14 front and a 140/70-14 rear.

FYI power by pcx sells a 13" version of the stock rims.

[kramnala58]

I'm running a 120/70-14 front and a 140/70-14 rear.

Same size as mine, and I love them. City Grips.

[Mgalutia88]

kramnala58, if you put your pcx on the center stand and twist the throttle, does the rear tire move in and out? or is it perfectly steady and balanced?

I have found that the Pirelli 140/70-14 vibrations are canceled at highway speed, BUT they CRACKED one of the three exhaust mounts. I am going to order Pirellis in the stock size and see what I think. Then I will be able to give an opinion between sizes on NEW tires.

[dasshreddar]

kramnala58, if you put your pcx on the center stand and twist the throttle, does the rear tire move in and out? or is it perfectly steady and balanced?

I have found that the Pirelli 140/70-14 vibrations are canceled at highway speed, BUT they CRACKED one of the three exhaust mounts. I am going to order Pirellis in the stock size and see what I think. Then I will be able to give an opinion between sizes on NEW tires.

My Pirellis work fine no wobbles/vibrations

cracked exhaust mount from the tire

[Mgalutia88]

I'm pretty convinced it's the shop I took them too. They didn't lube them all the way up the sidewall lol. I may try one last time. It's just getting annoying. I'm thinking a good bit of my speed loss is due to the unbalanced effect of the tire. At least for sure the overall diameter is slightly off lol.

[Mgalutia88]

Dasshredder can you also please put yours on the center stand to double check? Maybe I just have had a poor mount job.

[dasshreddar]

Yeah mines running true.
Un seat the bead and lube it good.
or maybe air it down to 10 pounds or so, and just cruise around your driveway to seat it better???

[Mgalutia88]

Thats a unique idea dasshreddar. If it doesn't seat it all the way out it may pop it off the bead... I like lol

[Mgalutia88]

Well, tonight I broke the bead on the front and rear tires and used plenty of tire lube to reseat the beads. I have no change from this. I am going to contact motorcycle superstore from this point and see what they will do. I am going to try to exchange for stock size Michelin City Grips. I was talking with Pcxdemon earlier and he has also had a slight out of round issue with his stock size pirellis so I am going to say at this point I don't recomend Pirellis on our bikes in the stock sizes or plus sizes.

Again I do NOT recomend the Pirellis because of poor construction.

[dasshreddar]

I would like to add... maybe just the Pirelli diablos are crap. My Pirelli gts 23/24 are fine and seem just as good quality as my Michelin city grip and Pirelli sl26 that are on my gy6/ruckus.
I was wrong I guess "you will have that 140 off in a week"
Why not try the city grip in a 140?

[Mgalutia88]

Not in a week. It's got 500 miles on it and I'll add more today. I think I'm going to go back with the stock size in a city grip. I was hitting an indicated 75 easy and topping at 80mph with the old dunlops. I'm interested to see what happens with a fresh tire back on...

[sendler2112]

3. Will I loose performance - Yes. 2-3 miles per gallon. Also the speedometer will be off by several mph. Acceleration is ever so slightly hindered. Top speed will be reduced by SEVERAL mph because of the larger mass being moved.

The mass of the tire will have nothing to do with top speed. It will only change how long it takes to spin up to that speed.

[dasshreddar]

I'm not sure what gearing you have, but with the stock gears my actual speed is 4mph faster than the speedo with the 140.
So 20mph(speedo) is actually 24 mph(gps) --- 70mph is actually 74mph etc.
Oh and if you can't return the 120 why not try that on the rear...or just keep it on the front?

[iceman]

I'm not sure what gearing you have, but with the stock gears my actual speed is 4mph faster than the speedo with the 140.
So 20mph(speedo) is actually 24 mph(gps) --- 70mph is actually 74mph etc.
Oh and if you can't return the 120 why not try that on the rear...or just keep it on the front?

Makes sense - for every rotation of the axle, a large diameter rim means more ground covered, so should outway any slight extra mass being carried. Same works for cycles - large wheels, more ground covered per rev.

[sendler2112]

I'm not sure what gearing you have, but with the stock gears my actual speed is 4mph faster than the speedo with the 140.
So 20mph(speedo) is actually 24 mph(gps) --- 70mph is actually 74mph etc.
Oh and if you can't return the 120 why not try that on the rear...or just keep it on the front?

This doesn't make sense either. a bigger diameter tire should increase speedo error by a percentage. 4 mph fast at 70 should be 1 mph fast at 20.

[Mgalutia88]

SENDLER, the real reason I probably lost several miles per hour is because of the tires being out of round. That imbalance along with an increase in mass and a low power engine means it's requires more power to turn which I'm lacking so it makes it harder to get there. I hit 77 mph today but it was not easy to get there. In contrast with the stock tires I was able to hold 70mph almost anywhere, could cruise at 75 easily and could hit 79-80 mph. With the oversize tires I cruise at 65mph at 2/3 throttle at 8000rpm.

[pricca]

Hi Guys,

My first post here, and a fellow 2014 PCX 125cc rider from Portugal

After coming from the SYM GTS/EVO 2 125cc world, the PCX feels a bit too unstable for me so I was looking to fit wider tires.

@kramnala58 and @Mgalutia88, did you have to change anything to fit these wider city grips to your bikes?

Thanks in advance for your answers

Ride safely
Pedro

[buddy1976]

Hi Guys,

My first post here, and a fellow 2014 PCX 125cc rider from Portugal

After coming from the SYM GTS/EVO 2 125cc world, the PCX feels a bit too unstable for me so I was looking to fit wider tires.

@kramnala58 and @Mgalutia88, did you have to change anything to fit these wider city grips to your bikes?

Thanks in advance for your answers

Ride safely
Pedro

Stock size city grip should be sufficient, I changed mine to city grip, my scoots now scraping the road when cornering to way before worrying about about losing traction. They seem more stable in rain than the irc's do in the dry!