restoring Merkur- solid T5 driveshaft....yay or nay? Ultimate goal is Gravel spec once cage is in. Have any of you XR guys used one? I have a chance to get it local for $100 https://www.rallyanarchy.com/phorum/read.php?5,104338,104338#msg-104338 Sat, 27 Jun 2026 07:12:56 -0500 Phorum 5.2.15a https://www.rallyanarchy.com/phorum/read.php?5,104338,104450#msg-104450 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104450#msg-104450
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john vanlandingham
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Clayto
I have a stock spare already and its in great shape.
Was thinking of getting the straight one piece for durability and no guibo to fiddle with.

No Guibo right next to a cat is good... One piece SEEMS to make sense in a car that the motor sits still and the diff is fixed like in IRS.

However.

We can review known knowns
Seems like every IRS car I can think of in rally use---and that's EVERY AWD car since beginning of time---and a lot of others retain the 2 piece design...
I don't understand why but they do. Group N they must by rules, Group A they can do whatever they want---and they all retain 2 piece....Probably a good reason..

We know they all retain 2 piece....we don't know why they do or if its know big deal (and certainly if it were BETTER-er to have 1 piece for any reason, all these works cars in last 30 years would have one piece..

There's something in driveshaft design called "critical speed" and length and rpm are factors, so I think it MIGHT be smart to look into driveshaft critical speed before making any decision...

The other thing is: you wanna pay twice? What box is going to be in this? Might be nice to nail that down before deciding on propshaft design.

But as I said i don't know anything about propshafts..


this might be a help in thinking ^
Still thinking..JV I finally got the measurements.
56.75" from end of yoke to pinion flange
2.5" diameter]]> Clayto Construction Zone Fri, 13 Feb 2015 23:21:10 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104401#msg-104401 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104401#msg-104401 NoCoast Construction Zone Thu, 12 Feb 2015 11:55:06 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104395#msg-104395 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104395#msg-104395 jbass Construction Zone Thu, 12 Feb 2015 06:46:26 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104390#msg-104390 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104390#msg-104390
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Robert Culbertson
Mostly correct. I'm not trying to be a dick and correct you, just making sure that accurate information is conveyed.

Precision and accuracy are optional around here.

I don't know what my shaft was other than it had two U joints and a center support bearing. No guibo thank god. Or did it have a Guibo. I don't recall. Regardless, Mark will have it in two weeks.]]> NoCoast Construction Zone Wed, 11 Feb 2015 17:23:31 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104389#msg-104389 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104389#msg-104389
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john vanlandingham
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Rallymech
Why is there no difference between mild steel and chromoly? Same modulus?

Yeah. all ferrous metals--even cast iron--have the same...(iron just doesn't have the fatigue resistance....)

Mostly correct. I'm not trying to be a dick and correct you, just making sure that accurate information is conveyed.

Grey cast iron has a Young's Modulus range of ~10,000 (about 6061 aluminum)-25,000 ksi, while almost all carbon steels and cast steels are 30,000 ksi.

The yield and ultimate strengths are what set different grades of steel apart the most. With mild steel being about 12% weaker than 4130.

Source: http://www.engineersedge.com/manufacturing_spec/properties_of_metals_strength.htm]]> Robert Culbertson Construction Zone Wed, 11 Feb 2015 16:51:22 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104388#msg-104388 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104388#msg-104388
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john vanlandingham

Whatever the case it sure is spoooky thinking about sumpin only 035" of sheetmetal away is spinning at 6 or 7 thousand rpm right next to my butt. Yikes

And here this whole time I was more worried about those big trees going by outside the window at 0 rpm!!! :eyepop: Yeah, I don't want anything up in my ass like timmo either....





In all seriousness, thanks for the input john. :beer:]]> MarkHille Construction Zone Wed, 11 Feb 2015 15:45:49 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104386#msg-104386 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104386#msg-104386
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Rallymech
Why is there no difference between mild steel and chromoly? Same modulus?

Yeah. all ferrous metals--even cast iron--have the same...(iron just doesn't have the fatigue resistance...ya snows bend it CRACK!)

What ever since it is clear theres a relationship tween dia, length and critical speed and for a given dia the speed goes down maybe the whole deal with retaining 2 piece on like fast IRS cars is each piece is kinda short..
Whatever the case it sure is spoooky thinking about sumpin only 035" of sheetmetal away is spinning at 6 or 7 thousand rpm right next to my butt. Yikes




]]> john vanlandingham Construction Zone Wed, 11 Feb 2015 13:25:32 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104385#msg-104385 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104385#msg-104385 Rallymech Construction Zone Wed, 11 Feb 2015 12:42:28 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104384#msg-104384 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104384#msg-104384 I'm waiting on exact length from seller.
Here's the ad info.....

"Looking to sell my 1-piece T5 XR driveshaft. It is steel
The pros:
-No guibo
-No center support bearing to align
-No vibrations (personally tested up to 145mph)
-No adapters necessary
-Good u-joints, although regreasing is recommended as it's been sitting for a few years.
The cons:
-Paint has worn off from rock chips and the sort. Could be repainted if this is something that concerns you.
-A little too long, requires loosening the trans mount and front sway bar to install
located in Vancouver, WA. Would rather not ship due to size."

Straight and simple is what I'm looking for and if the length is good I'll grab it:)]]> Clayto Construction Zone Wed, 11 Feb 2015 11:20:35 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104382#msg-104382 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104382#msg-104382
But...when I was pricing them out it was going to be well over double in price. Then there is the maintenance involved (guibo and that bracket thingy). Then there is properly fitting the bracket. Then there is you run over one big rock and your out of the rally and need to spend the same $$$$ on the replacement.

I could see if it was a safety issue but I have never heard anything about a one piece failing in a Merkur. I specifically asked some of the auto x guys who have been running them for years. The vibration only presents itself as a noise and not an actual vibration so it doesn't affect the drive and it mostly seems to come from the transmission. The more solid your transmission is mounted the louder it seems to be. If you still have all your sound deadening you may not even notice.

My shaft is 3.5" and 48" center to center. If you don't get a 0.80 5th gear you will never use 5th gear. In 4th that puts the ratio at 1:1 and with a stock rev limit of 6500rpm it falls well under the 8700rpm critical speed in the chart. No?

I paid $300 out of the door for mine. I could have gotten two of them and had a spare for less than what I was getting for quotes on a two piece. Some people were modifying their stock two piece shafts for not a ton of money but of the 4 stock drive shafts I've seen they all would have been more likely to fail than the one piece I have. Didn't Sean have a two piece that failed during a rally?]]> MarkHille Construction Zone Wed, 11 Feb 2015 08:44:07 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104374#msg-104374 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104374#msg-104374
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Clayto
I have a stock spare already and its in great shape.
Was thinking of getting the straight one piece for durability and no guibo to fiddle with.

No Guibo right next to a cat is good... One piece SEEMS to make sense in a car that the motor sits still and the diff is fixed like in IRS.

However.

We can review known knowns
Seems like every IRS car I can think of in rally use---and that's EVERY AWD car since beginning of time---and a lot of others retain the 2 piece design...
I don't understand why but they do. Group N they must by rules, Group A they can do whatever they want---and they all retain 2 piece....Probably a good reason..

We know they all retain 2 piece....we don't know why they do or if its know big deal (and certainly if it were BETTER-er to have 1 piece for any reason, all these works cars in last 30 years would have one piece..

There's something in driveshaft design called "critical speed" and length and rpm are factors, so I think it MIGHT be smart to look into driveshaft critical speed before making any decision...

The other thing is: you wanna pay twice? What box is going to be in this? Might be nice to nail that down before deciding on propshaft design.

But as I said i don't know anything about propshafts..


this might be a help in thinking ^]]> john vanlandingham Construction Zone Tue, 10 Feb 2015 21:41:32 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104373#msg-104373 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104373#msg-104373
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MarkHille
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Clayto
Ultimate goal is Gravel spec once cage is in.
Have any of you XR guys used one?
I have a chance to get it local for $100

What is the diameter? I have one going from a t5 to a supra diff. Its not really interchangeable with the stock diff so if you have a stock diff and want to change it you might have to make some changes to the driveshaft. Is it custom ($350ish new?) or is it just a mustang shaft with spacer? I wouldn't mess with the mustang one. Either way, you should expect a ton of scary vibration noise from the driveline that seems to be notorious in an XR with a solid shaft but longevity doesn't seem to be an issue. For a daily driver I'd say don't do it. For a race car it seems the best/strongest option.

Not sure on diameter....It's a custom driveshaft. Fits to a stock housing.
I think I'm gonna get it and put it in my parts pile.
Previous owner had it 60,000 miles with no vibration problems.
Wife is going back to work after 8 years raising kids.... Stoked for her new job and for some of my Budget back:)]]> Clayto Construction Zone Tue, 10 Feb 2015 21:16:20 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104361#msg-104361 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104361#msg-104361
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Clayto
Ultimate goal is Gravel spec once cage is in.
Have any of you XR guys used one?
I have a chance to get it local for $100

What is the diameter? I have one going from a t5 to a supra diff. Its not really interchangeable with the stock diff so if you have a stock diff and want to change it you might have to make some changes to the driveshaft. Is it custom ($350ish new?) or is it just a mustang shaft with spacer? I wouldn't mess with the mustang one. Either way, you should expect a ton of scary vibration noise from the driveline that seems to be notorious in an XR with a solid shaft but longevity doesn't seem to be an issue. For a daily driver I'd say don't do it. For a race car it seems the best/strongest option.]]> MarkHille Construction Zone Tue, 10 Feb 2015 13:37:51 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104343#msg-104343 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104343#msg-104343 Was thinking of getting the straight one piece for durability and no guibo to fiddle with.]]> Clayto Construction Zone Sun, 08 Feb 2015 20:04:50 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104341#msg-104341 Re: restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104341#msg-104341 fiasco Construction Zone Sun, 08 Feb 2015 18:53:20 -0600 https://www.rallyanarchy.com/phorum/read.php?5,104338,104338#msg-104338 restoring Merkur- solid T5 driveshaft....yay or nay? https://www.rallyanarchy.com/phorum/read.php?5,104338,104338#msg-104338 Have any of you XR guys used one?
I have a chance to get it local for $100]]> Clayto Construction Zone Sun, 08 Feb 2015 13:13:14 -0600