1157 vs 1034 bulbs - never knew this

[TR1957]

I thought I would post this as an FYI. I looked but didn't see any reference to these bulbs on the forum.

The rear lights on my '57 Chevy were 1157’s which I was quite familiar with.However, the bulbs I took out ofthe front parking/turn signal lights on the ’57 (I am pretty sure were neverreplaced); were 1034’s. I had never seen these before. I thought they were somereally obsolete bulb which was replaced by the 1157. Both have dual filamentsand both have identical sockets. Upon doing some research I found the 1034 hasa definite advantage to the 1157 in specific situations. I never knew this.What is key is the secondary filament and using your turn signals.

I found this clear explanation on eHow.

Difference Between 1034 & 1157 Car Bulbs


By David Sandoval, eHow Contributor
Automotive lamps burn out after a long period of use. Often, more than one bulb can serve as a replacement part for nearly any automotive lamp. For example, an 1157 automotive lamp is electrically compatible with a 1034 lamp. However, some notable differences between the two lamps may make one better than the other for your specific situation.



Primary Filament Operation at 12.8 Volts

The primary filament is used for normal marker-lamp (the rear light that comes on when you turn on your headlights) operation. The 1157 lamp can sustain 2.10 amps at 12.8 volts, and will last an average of 1,200 hours. The 1034 lamp can handle 1.80 amps at this voltage, and will last an average of 200 hours.

Secondary Filament Operation at 14 Volts



The secondary filament is used for turn signal operations. The 1157 lamp can sustain 590 milliamps of electrical current at 14 volts, and lasts an average of 3,000 hours. The 1034 lamp lasts an average of 5,000 hours under these conditions.

Considerations When Choosing Which to Install



Since both lamps are used as combination turn-signal and marker lamps, choose the lamp that suits your needs best. If you do a lot of daytime driving and require a long-lasting signal lamp, install the 1034 lamp. If you do a lot of nighttime driving, and do not need to use your turn signals often, choose the 1157 lamp.

[chevynut]

Well this doesn't sound right to me. The current through an incandescent lamp filament depends on the resistance of that filament. The higher the resistance, the lower the current. The power it consumes is I x V (current multiplied by voltage). The more power, the brighter the bulb is. The more power, the lower the life of the bulb, all else equal.

They claim the 1157 primary filament pulls 2.1 amps (27W) at 12.8V, and lasts 1200 hours. Then they claim the 1034 pulls 1.8 amps (23W) and lasts 200 hours. First I can't believe the higher power bulb lasts longer....and 6 times longer? This must be a typo....I believe the 1034 would last longer than the 1157, and the 200 hours is probably really supposed to be 2000 hours.

Next, they say the secondary filament is for turn signals. The turn signal is usually brighter than the tailight. On a tri5 the turn signal filament is the same as the brake light filament. So how can the 1157 only draw 590 milliamps (8 W) at 14 volts? This filament would be a lot dimmer than the primary filament. And why did they change from 12.8 volts to 14 volts? They didn't give the current that the 1034 draws but claim it lasts 5000 hours, so it should be less. And the light output would be less too.

This article seems phony to me. Nothing makes any sense. I don't believe whoever wrote it knows anything about electricity. The conclusions are flawed as well. IMO.

[Rick_L]

I think you hit all the number trends correct. I.e., 200 hour life s/b 2000 hours, and the functions are reverved (23 watts vs. 8 watts). Who knows if any of the numbers are accurate?

And why are the voltages different?

I do know this, if your regulator fails and the voltage climbs to 18 or 20V, you'll blow out every bulb in the vehicle that's on - in a a short time. So the life must be inversely proportional to at least the cube of the power, or even more so. But the lights will be really bright for a short time.

[chevynut]

Rick, remember that power is Voltage SQUARED divided by resistance. So if voltage doubles, power quadruples and life probably drops by at least 75%...probably a lot more. The point is, even going from 12V to 14V increases power 36% so life drops considerably.

That "article" is full of misinformation. Don't believe everything you read on the internet without verification.

[Run-em]

Don't think the average 55-57 Chevy owner is concerned with the lifespan on either of those bulbs....just which bulb is brighter in order to avoid an accident.

[ilike55s]

While I never did a "side by side " test of the two, I always felt the 1157's were a tad brighter. But, when I was growing up and me being "thrifty" I always put in what was available at the parts store,,,,,:)

[br13]

The life of an incandescent filament depends on its operating temperature. Hotter filaments generally don't last as long.

Some applications use a longer piece of slightly larger tungsten wire for the filament to achieve the same resistance and power. it will be a little less bright, but last longer at the same voltage and power.

Brightness depends on both filament temperature and filament power.

[ntfday]

I realize this thread is a year old, but I would suggest that you don't mix 1157's and 1034's. A few years back I had a buddy that had a 68 Ranger and every time he pressed on the brake pedal the dash lights would glow. He went so far as to replace the dash wiring harness to no avail. The problem was that he had a 1157 in one tail light and a 1038 in the other. The lighter filaments of the 1038 was providing feedback to the dash lights.

[Rick_L]

I have a difficult time buying in to this. I think there was a wiring problem.