Some user notes on the 7.5HP motor

There are some very steep winding hills nearby that provide a good view on a clear
day. They are like the ones you see in a car commercial from the aerial view of the car
tracking these long curvy steep hills. I decided to take a spin up to see how the new motor would
handle it.

Going up was no problem but coming down was another issue. As most know,with
the 7.5hp motor on the '05 and later the odometer reads half speed and half miles
traveled. Since the governor is disabled one most rely on the brakes only. This issue I believe is unique to 2005 GEMS & later

I did make it down OK but was concerned for the condition of the brakes. I
thought about putting it into low gear but thought 30mph was still too fast (15=30mph).
Perhaps I will do a shorter test run to see if 30mph is better then riding the brake 2 miles
downhill.

I was hoping that the controller could be reprogramed but according to a reply to this posting on the Yahoo NEV group it can't be regrogramed to regen at anything other then 15MPH 0r 25mph. This leads me to believe that '05's and later GEM's do not regen with the 7.5HP installed. I was told it would by Ride-4-Fun thta it did regen. If I'm right I don't think they misled me on purpose but simply got confused with the model year or assumed it did. So for now I have to be aware of hills and it's a shame not to regen when dealing witht them

BATTERY LIFE

New Motor Installed

I installed the ride-4-fun's 7.5 HP motor in my '05 GEM. It installed pretty straight forward. Earlier models may require moving a shock absorber or at least removing the tire to install - confrm with your vendor before buying!

Simply turn off the main power, remove the electrical wires, remove the motor, remove a rubber gromet in the old motor and place in the new motor shaft. Slip the new motor on apply some blue locktite to the 3 screws that hold the motor in place

The motor can be purchased from other vendor's for pre-'04 models but in the '05 and later models GEM made some changes that make it more difficult to increase the speed. Basically the controller needs to be fooled into thinking that the car is traveling below 25MPH. They achieve this by shipping a motor with 4 magnets instead of 8. This makes the speedometer read half the actual speed and the odometer half the actual distance. By doing this the speed govenor never kicks in. So when the speedometer says 15, one is actually traveling at 30, and so on.

R4F told me they can reprogram the controller (this is included in their price) but only to a certain amount. Not as much as the pre '05 models. The reprograming, as explained to me, is increaseing the amount of power (electricity) that can be delivered to the motor. The downside of this is that it depletes your batteries that much quicker. I have yet to send my contoller in for reprogramming.

UPDATE: (5/27/07)
My motor fried about a week and a half ago. It only had a bout 70 miles on it and Jim at Ride-4-fun was baffled. I sent it back to D & M Motors in Syracuse for evaluation. Jim said he is only aware of 2 failed motors and they were a result of customer abuse. I can say without any doubt that this motor was not abused.

more later .. .Oh yeah, the motor kills the batteries. You really have to be careful and only use the extra power when you know you driving plans. more details later

UPDATE: (7/2/07)
I've had the motor installed for about 2 weeks now, other than some residual electrical burn smell - I hope - it seems to running fine. I have started a blog with some notes on the reality of a 7.5HP motor, see "Some user notes on the 7.5HP motor "

What is a GEM

A Gem is basically a street legal golfcart.

Having said that, the GEM (Global Electric Motorcars) car is classified as a NEV. In 1995 the Federal Government created the NEV vehicle classification to encourage enviormentally friendly forms of transportation. The idea coming from the statistic that something like 60-70% of the mileage traveled with a household's second car is 10-15 miles. The NEV classification creates a vehicle to serve this statistic. It is for people who travel & stay locally - taking the kids to school, daily errands around town, the short commute to work, etc.

An NEV must meet these requirements:

• Headlights
• brakelights
• seatbelts
• back up beeper
• turn signals
• windshield & wipers
  
• horn

It has a maximum speed of 25mph and may be driven on streets with a maximum limit of 35mph.

GEM is a specific make of NEV. It is made in South Dakota by Glogal Electric Motorcars, which is a division of Chyrsler. It is the most popular NEV. There are many other manufacturers of NEV's as listed on the parent website of this blog - Zenn, Big Man, etc. Some look more like conventional cars.

GEM car pros/cons

PROs

• From a safety perspective it is an eye catcher - other drivers see you
• Obvious savings on gas and greenhouse emissions
  

CONS

• Safety issues
• hair gets attcked by wind (can add doors)
  
• If it's cold outside, it's colder in a moving GEM, although a heater is a factory option as are hard doors
  
• range - "up to 30 miles" this is in a perfect enviorment. If you live in a relatively flat area you are probably looking at 25, with hills about 20
• Battery life and charger updates. The batteries need to be maintained if they are the classic "flooded" batteries - maintain the water level. Earlier GEMs have an incorrect charging curve for the batteries and needs it to be updated. Sealed maintence free batteries are available but cost more. If you change battery types then the charger needs to be updated
  

Another thing to think about is that you must modify your driving habits. Even though the NEV is legal on streets up to 35MPH it is best to avoid these roads when possible, for safety reasons and as a curtisy to you fellow drivers. Let's face it most people don't want to get caught behind a car travel 25mph (at best).

Your travel time time frame must change too. Other then driving in rush hour traffic when everyone doesn't get very far you must allow more time for driving greater distances, that is if you plan on using the NEV much.

Several states (Montana come to mind) have recently introduced a new classification of MSV (Medium Spped Vehicle) that have a maximum speed of 35mph. This is a more practical speed

tires

When I first took delivery of my 2005 GEM I thought I would drive it to see how I would like the 25MPH speed restraint that is built into the vehicle. I also was aware of the possibility of modification.

After driving it a few times I felt the need to have more power. Not to go crazy but to navigate the 35MPH streets more effectively. I have to deal with some inclines on a regular basis and the stock 2005 GEM that I drive will slow down to about 20mph when tackling it, with a full charge.

Now I'm a fairly curtious driver with my GEM. I make sure I take the side roads when traveling in the business district as not to slow things down and I tend to pull over whenever I can to let cars pass.

Having said that it basically is no fun when I have to go up and over the local freeway and slow all the traffic. It would be very nice to be able to at least do 25MPH up the hill and perhaps close to 35 on the flats when needed.

One of the ways to increase speed is to increase the tire size. Going from my stock 12" rims with 165/65/r12's to 175/65/r14 will result in a increase of 3 mph according to the Gem speed options spreadsheet. It may not seem like much (and can be a pricey upgrade) but coupled with a motor upgrade from ride-4-fun the my GEM could get close to 35mph

After some very helpful replies to my posts on the Yahoo NEV forum I found out the following:

24" or just under total diameter tire size seems to be the magic number. Anything more then that may rub, especially with the rear spat and when turning. It also depends on the year of your GEM (the earlier GEMs had 10" rims and the chance of rubbing is greater, however you will get a larger speed increase when oversizing the tires on these models plus they have a lower gear ratio so that adds to the speed increase.

What are the options
The goal is to increase the diameter of the wheel. When you increase the size of the tire you gain more distance per axle revolution. The GEM uses a 4x4 lug pattern, this is common to trailers and golf carts

• The least expensive option is to purchase 13 trailer rims with 4x4 lug pattern and "0" offset. The offset is the amount that the mounting portion (the part with the lug holes) is offset to the inside or outside of the rim. GEM's have "0" offset as do standard trailer rims (alloy wheels made for trailers may have an offset). Rims and tire combos can be purchased from companies such as Northern Tool and etrailerparts.com. You can find them with and w/o tires. The largest size in a 4x4 lug pattern is 13" & generally you can put a 175/80/r13 tire on the rim and have 24" diameter. With this option you can probably keep the cost to less then $100 a wheel. The down side on the cheap ones is they are made of steel.
  

• The other option is to simply use alloy wheels that you would normally put on a car. It is more expensive but arguably cooler looking. You can even go to a low profile wheel / tire combo as pictured right. Most alloy / sport wheels have some sort of offset and do not come in a 4x4 lug pattern. This requires the use of wheel spacers /adapters. The adapter will go from one lug pattern to the other and return the wheel to a "0" offset. All wheels will say what their offset is.
  

I saw the wheel kits and thought perhaps I could put something together myself and save some dough, especially since I found out later that I paid too much for the GEM - I didn't get taken but I could have done better with an old model - that's a different blog.

To keep cost and weight down I decided to keep the rim size at 14" and go with a higher tire (175/65/r14) resulting in a total height of 23" even. Intially I thought I would go for a 23.5" total height with a 185/65/r14 tire but since I was mostly buying over the net I wasn't going to be able to return the items practically if there was aproblem I decided to keep it conservative. There is only a 1/2 mile per hour difference between the 23 vs 23.5" wheel height.

I decided to purchase pep boy wheels choosing the 950 series. I think the low profile wheel/tire packages look cool but may not provide the best battery life (distance). I wanted to keep the weight down and not go with an overly wide tire, as these tire/wheel combos tend to have. I also heard about something called "Low Rolling Resistance" Tires. Based on the yahoo users group I decided to go with a Bridgestone Ponteza RE92 on the pepboy rims from Tirerack.com.

I was also directed to contact wheeladapters@aol.com. They are an ebay vendor and evidently have the best price on the correct adapter/spacer needed for what ever rim one purchaes. Although the correct wheel spacer for the 38mm offset that these new rims have is 1.5" I was told that the 1.3" is close enough. They also ship with lug nuts

Another option is to simply go to Craigslist.org and find a used set locally but I found that most rims were not going for less then $50 each and did not have the tire I wanted on them.



INSTALLATION
Installation is fairly straight forward. The only thing I did that was different was I used the OEM lug nut for the adapter and the adapter lugs for the new rim. The reason was because the bevel on the adapters lug (right) fit the Pep Boys rims better then the OEM lugs. This eleiminated some play that was present.

The adapters went onto the rear wheel of the GEM with out a hitch. I had jacked the GEM up so that both rear wheels were off the ground. This was OK since the parking brake kept the wheels locked while tightening the adapter onto the brake drum.

However, when doing the front wheel I did the same thing - lifting the whole front so that both wheels were off the ground. The problem with this is that when one wheel is spun the other wheel spins. This makes it difficult to tighten the lug nuts. To stop the wheel from spinning I placed a screwdriver in between the studs that hold the disc brake & lug plate. In the process of doing this I think I dislodged the disc for the brake on one of the wheels because it squeaked when I finally drove the car. I intially thought I bent the disc support studs. I eventually applied the brakes very hard in quick succession (partially out of frustration) and the noise stopped.





BUDGET

Potenza RE92 175/65/14 - $61 each (4x61=$244 + $47 shipping) = $293
wheel adapters - $129
Rims - $218
mounting/balance - $45

TOTAL: $685

Ride-4-fun's comparable 14" kit is $799 (plus $150) shipping. Their's is a low profile tire and probably not a LRR tire. They did tell me they use a 1.5" spacer / adapter. In the end I saved about $250 and perhaps got a better tire.

WEIGHT
The difference between the old tire/rims and new ones is approx. 6lbs each. The particular rim I bought is made of aluminum. I don't remember what the adapters weigh but I want to say the grand total of additional weight was around 40-50lbs.





























New Tire on left















Size difference