Why a Modern Gear-Reduction Starter Makes a Wise Upgrade

In most cases, there is nothing inherently wrong with the starters that came on our classics. Like a noble workhorse, they step up and do their jobs over and over again. The problem is that many of these units have been doing that job for 40 or 50 years. Just like that workhorse, these starters need to be put out to pasture sooner or later. While we view some conversions with skepticism, modern gear-reduction starters are one upgrade we can get behind. 

Historically, car owners would send out their original units for a rebuild and everything would be fine. Unfortunately, these days there are fewer quality rebuilders out there, fewer rebuildable cores to work with, and fewer parts available. Rebuilt starters have been more like a gamble than a sure thing, and most of us want to bank on a sure thing when we need to start our cars on a rainy night.

Recently, brand-new reproduction units have begun to show up. A few of these pieces are simply too expensive, while some offshore models leave us wondering if they can weather the decades like their OEM counterparts. Others, however, show promise.

Enter the compact gear-reduction starter. Based on the mainstay of modern starters, these units operate on a different set of principles than their ancestors. Instead of using a relatively large, torquey motor that spins slowly, these modern units use a relatively small motor that doesn’t have a lot of torque but can spin quickly. 

They rely on a reduction gearset to convert high speed to low speed and low torque to high torque. The result is a starter that isn’t as stressed and has the potential to hold up for a longer period of time. Several manufacturers have built adapters to mate these modern starters to our classics, meaning this upgrade can be a bolt-on affair.

The major benefit is that these units tend to be very reliable. However, there is a caution: Stick to reputable sources, as there are many fly-by-night outfits selling poor-quality products. (Search for gear-reduction starters on eBay to see how many “companies” are selling these units.) Purchase them from a reliable source, and we feel that these starters should deliver many years of service, allowing you to spend time on other parts of your car. 

These starters are also smaller and weigh less than the units they replace. Shedding some pounds and gaining a little extra room is a double bonus that most of us would gladly take. Our chart below shows how much weight can be saved.

We’re not through with the benefits. These starters also generally use less current to operate. We find that the average gear-reduction starter draws about 100 amps, while their OEM counterparts can draw more than 130. 

This means if the car isn’t frequently driven, it may not need a charger or jumper pack to start. You’ll also find that these starters are less susceptible to losses due to corrosion or bad terminals, although that’s not a reason to let the car suffer, either.

The final benefit applies to cars that use starters featuring a “crash” bendix. These starters are notorious for destroying ring gears, as they slam into the backside of the flywheel ring gear. Gear-reduction starters use a pre-engaged bushing and gear arrangement that more accurately meshes with the front side of the ring gear. 

Not only is this much easier on the ring gear, but in some cases it allows a damaged ring gear to remain in service. Remember, it’s easier to swap a starter than to pull a flywheel and swap ring gears.

Sound too good to be true? There are downsides. One is the aforementioned quality issue. Some vendors are simply not putting out a good product. 

Another issue is fitment with certain cars. While some of these starters fit very well, some barely fit at all. They may require rerouting or replacement of the main battery cable, as the new mounting location can render the cable too short. We’ve also seen some setups that have the potential to short if a distributor clip makes contact. 

Take-home message to all of this: In most cases, a gear-reduction starter is lighter, more reliable and more efficient than the one originally fitted to your classic. However, upgrading to such a unit should involve some research. While there are excellent turnkey solutions out there, you may have to weed through a few substandard options.

1. When it comes to vintage starters, there are two basic types. The top one uses a “crash” bendix and external solenoid. It’s common to MGAs, Spridgets and some TRs. The bottom is a pre-engaged MGB starter that features an integrated solenoid.

2. Our Modern Midget project car received a modern gear-reduction starter during its construction, as our OEM Lucas starter—shown here—was getting a little noisy. 

3. We sourced a gear-reduction starter from Gustafson Specialty Products. The smaller, modern unit is nearly half a pound lighter than the piece it replaces. It also requires about 100 amps to spin the motor over; the OEM unit demanded 130.

4. Since our Midget uses an external starter solenoid, we had to fit a jumper wire from the unit’s big post to its small post. We could have eliminated the solenoid completely, but our solution leaves more of the stock wiring intact while requiring less work.

5. Many gear-reduction starters can be rotated into different positions for easier mounting. Our unit came positioned properly, so we didn’t change anything.

6. Our Midget’s new starter should last for thousands of happy starts.

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View comments on the CMS forums
wspohn SuperDork
8/3/20 4:47 p.m.

Given that the gear reduction starters tend to cost between double and 2.5 times what the original style did, one has to think a bit before going that way.

I own several cars that use BMC B series engines and the late style of pre-engaged starter has considerably more grunt than the original early starters did and because they pre-engage with the teeth before exerting torque, they are bolt in replacement for the early style despite the fact that the ring gear teeth are chamfered the opposite way.  I run a stock late MGB starter on my race engine, which is 12:1 compression and is a fairly stiff challenge to a starter and the stock late style BMC unit performs just fine.

Given the possible misfitting issue that you mentioned and the large price differential, I tend not to bother fitting the gear reduction style.


CAPTREJohnston New Reader
2/1/21 1:16 p.m.

Putting a modern gear reduction starter in my 1973 Alfa Romeo Spider in 2014 was the single best modification I've made to it in my 47 years of ownership.  The difference in the speed with which it cranks the engine over is night and day compared to the origianl Bosch starter.

Tim Suddard
Tim Suddard Publisher
2/2/21 6:20 a.m.

I use them in almost all the project cars I build and have never had a starter problem.

volvoclearinghouse PowerDork
2/5/21 1:07 p.m.

After doing a little research I discovered that Volvo used the same starter in the 1960's B18's (and probably even earlier in the B16's...) up through the 240 volvos in the 1980's.  Then around the mid-late 80s they changed over to a gear reduction unit.  Thus, while I have not yet confirmed personally, I'm strongly suspicious the later 240 gear reduction starters are a drop-in replacement for the heavy old starters in the B16/B18/B20 found in pV444, PV544, Amazons/ 122, 1800, and 140's. 

As it happens I have a new gear reduction starter out of a 240, and plenty of b18's/ b20's to try it in...

GrizwoldsZ New Reader
6/14/22 10:44 a.m.

I guess I'm lucky. I own a Datsun 240Z and a factory gear reduction starter from a later model 280ZX bolts right in. I've had this setup for several years now with no issues.

jr02518 HalfDork
6/15/22 9:26 p.m.

Adding the newer, smaller and lighter starter to my Datsun helps with room for the headers that will happen, in the furure.

Getting the original out of the car is no fun, but it happened.  Taking a page from the Lotus play book, lightness has been added! 


Tim Suddard
Tim Suddard Publisher
6/16/22 12:12 p.m.

In reply to jr02518 :

Wow, what a difference.

PeteLoBianco New Reader
6/16/22 6:58 p.m.

I'd express a little concern here if switching from a "crash" or pull starter to the push type.  Used to play with English Ford engines (Super 7) and we never switched types of starters without switching flywheels.  The pull type starter had a flywheel with the ring gear applied from the back.  The push type had a flywheel with the ring gear applied from the front.  In both cases it seated against a lip with the starter pushing or pulling against that lip.  I had heard (never experienced) horror stories of starters removing ring gears over time.  Is this not the case when switching on other British cars?

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