Taxis And The Size Of Their Rear Tires

[Mr Lee]

I have noticed often that taxis seemed to bottom out when we were in them and while I know I am a big boy at almost 6 feet tall and 210 pounds, my wife only weighs a little over 100 pounds so the combined weight should not be enough along with our suitcases to bottom out the rear of a newer taxi under normal circumstances so I felt a little investigating might be in order. Seems many of them use undersized tires on the rear to up the meter amounts, so this might be something members might want to keep an eye on or just be aware of when going to the same places often and the meter runs different amounts. It will be a big difference on longer trips.

[Jollygoodfellow]

I have noticed often that taxis seemed to bottom out when we were in them and while I know I am a big boy at almost 6 feet tall and 210 pounds, my wife only weighs a little over 100 pounds so the combined weight should not be enough along with our suitcases to bottom out the rear of a newer taxi under normal circumstances so I felt a little investigating might be in order. Seems many of them use undersized tires on the rear to up the meter amounts, so this might be something members might want to keep an eye on or just be aware of when going to the same places often and the meter runs different amounts. It will be a big difference on longer trips.

You may be right but I could not see undersized tires being the cause of bottoming out,they would have to be very under sized in my opinion.

[Mr Lee]

I have noticed often that taxis seemed to bottom out when we were in them and while I know I am a big boy at almost 6 feet tall and 210 pounds, my wife only weighs a little over 100 pounds so the combined weight should not be enough along with our suitcases to bottom out the rear of a newer taxi under normal circumstances so I felt a little investigating might be in order. Seems many of them use undersized tires on the rear to up the meter amounts, so this might be something members might want to keep an eye on or just be aware of when going to the same places often and the meter runs different amounts. It will be a big difference on longer trips.

You may be right but I could not see undersized tires being the cause of bottoming out,they would have to be very under sized in my opinion.

Not really because just two sizes means a lot in height and those Corolla's are low to the ground in the first place and probably not designed for big people in the first place when made in the Philippines. I really did not understand at first that a lot of cars and trucks are made to Filipino specifications and made in the Philippines, from seats placement to dashboards and probably springs and shocks. The first time I got to Mindanao, I got into a Ford Pickup truck and could barely fit my legs between the dash and the front of the seats because of the height of the seat and its placement and then I tried to get into the front seat of a jeepney we rented for the family for the day to go to the cemetery and there was no room for my feet and I had to turn them down and sideways to fit on the floor board because we were so close to the dashboard and firewall and I felt like a sardine in a can and could not wait to get out of there. I did not do that again after that one time and now the family goes without me when we are there because I just do not fit for the long ride and a sudden stop or accident would have broken both my ankles and legs. BTW, speedometer gears are made according to the size of the tires the car is designed for and therefore smaller tires change the speed the speedometer sees as well as the miles or in the Philippines and other places kilometers traveled.

[brock]

Tyre size does not alter the taxi meter reading.

Edited January 10, 2010 by brock

[Mr Lee]

Tyre size does not alter the taxi meter reading.

I beg to differ with you, the meter works on time and mileage and if the speedometer goes faster then the mileage increases, so the tire size changes the distance traveled and therefore will increase the meter. Could you explain why you feel that it does not? I used to be an auto mechanic when I was a teenager and I often had to change speedometer gears when people changed the size of the tires on new cars that were delivered.

[Guardian]

I can say for a fact that tire height changes speedometer speed and miles traveled, but maybe tire sizes may not if they are the same height.

[brock]

Tyre size does not alter the taxi meter reading.

I beg to differ with you, the meter works on time and mileage and if the speedometer goes faster then the mileage increases, so the tire size changes the distance traveled and therefore will increase the meter. Could you explain why you feel that it does not? I used to be an auto mechanic when I was a teenager and I often had to change speedometer gears when people changed the size of the tires on new cars that were delivered.

Just that I used to own the largest Taxi firm in lincolnshire county, going faster doesnt increase the milage covered.

[Mr Lee]

Tyre size does not alter the taxi meter reading.

I beg to differ with you, the meter works on time and mileage and if the speedometer goes faster then the mileage increases, so the tire size changes the distance traveled and therefore will increase the meter. Could you explain why you feel that it does not? I used to be an auto mechanic when I was a teenager and I often had to change speedometer gears when people changed the size of the tires on new cars that were delivered.

Just that I used to own the largest Taxi firm in lincolnshire county, going faster doesnt increase the milage covered.

Owning or being a mechanic and working on might be two very different things. You might wish to read this and if new tires verses old tires can change mileage traveled then surely smaller tires would change it even more. tire sizeWhen the GPS indicated exactly 100 miles had been traveled while the vehicle was equipped with new 12/32" deep tires, the vehicle's odometer registered 99.4 miles. When the vehicle was then equipped with another set of the same tires shaved to 2/32" of remaining tread depth, the odometer indicated 101.0 miles. While the 100-mile test distance didn't change, essentially the vehicle's odometer overstated the distance traveled by about 1.5% when equipped with the worn out tires.and then read this tootire size effects Tire size has the exact same effect as changing the gear ratio in the axle. Vehicles are designed with tires of a certain height. The width of the tire makes no difference, but the height does. Consider that a 27-inch tall tire needs to rotate say for example 400 times in an eighth of a mile while a 31-inch tall tire only has to rotate 320 times in an eighth of a mile. The taller the tire, the faster the vehicle will move for the same amount of RPM, however the speedometer will show a slower speed than what the vehicle is actually traveling. The reason for this is that the speedometer gear is set at the factory to indicate speed based on a 27-inch tire.Know the long-range implications of changing tires. A taller tire will give better fuel economy on the highway but worse in town, with less acceleration. The speedometer, unless corrected with a different gear for the present size tire, will show an inaccurate number. For example, the speedometer will show 50 miles per hour while the vehicle is actually doing 58. This also affects the distance traveled on the odometer. It will show less distance traveled than the car has actually traversed. It also affects the transmission shift points, which are set up for the smaller tire. Another aspect of taller versus standard size tires is that the taller the tire the softer its side wall and the worse the handling, since the tire has much more flex in the sidewall and the vehicle is much less aerodynamic.A smaller tire has the opposite affect on the vehicle. A smaller tire will have much better acceleration, be better in town but lose a little fuel economy over the larger tire. That's because it is turning faster or the engine is running at a higher RPM at 60 miles per hour than with the larger tire. The speedometer can be corrected by having the correct speedometer gear installed for the size tire being used.

[brock]

Hi Lee,I will not say you are wrong on this point as I have no mechanicle knowledge whatsoever, All I was going on was the fact that my Taxi`s all made the same journey at one time or another, and all fares were the same, give or take a few pence, So if what you say is right then i stand corrected.

Edited January 11, 2010 by brock

[Mr Lee]

Hi Lee,I will not say you are wrong on this point as I have no mechanicle knowledge whatsoever, All I was going on was the fact that my Taxi`s all made the same journey at one time or another, and all fares were the same, give or take a few pence, So if what you say is right then i stand corrected.

Not a problem my friend and we all learn and that is what forums are about and I keep learning every day and I appreciate everyone who gives their input so that I can learn but on this one I have been there and done that because I used to be a mechanic at a Dodge dealer when I was a kid and I used to race cars and have checked the speedometer against the speed they clocked me at and it was never even close when I had on large slicks (tires) for racing. Also, the car dealer I worked for had a book on different size tires and which different size speedometer gears they would use. I am sure calibration might be another reason that some taxis seem to charge more and then there is the old bump switch which make the meter jump and the guys who hide the meters in the ashtray are famous for those. My wife and I were in a taxi with Hoz a member here and I am sure he can tell you what happened but to make it short, the meter was flying like it was in an airplane and had already reached about what it should have cost us to get to where we were going and we had not even gotten off Mactan from the pier yet. I told the guy about his meter and he said we can negotiate a price for the trip and he would shut the meter off because he knew it was not only fast but was probably 5 times faster than it should have been or he hit the bump switch too many times already. Anyway we got a fair price and then when he dropped us off I gave him an extra p100 and told him that I gave it to him because I wanted to and not because he could rip me off with a fast meter and that I suggested he get it fixed or if I or anyone I know used him again and it was still fast, then I would make sure the LTO knew that he knew it was very fast, but my guess is he just did not care because it made him more money and that time it had nothing to do with the tires. IMO we that know cannot let them rip us off so that they do not do it to the tourists all the time.