'83 720 - Swapped to 700c, freewheel too close to dropout, fender bolt won't fit etc.
#26
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Thread Starter
7 speed freewheel is weaker than a 6 speed freewheel (unless one of those oddball skinny chain freewheels with the same axle size). Any freewheel is weaker than a hub.
As I said, I have bikes with freewheels I'm happy with, I have my heavy load tourer on a hub. On freewheel I prefer 5-speed freewheels, 120mm axles. The way freewheels work the longer you go on the axle/sprocket count the weaker it gets.
As I said, I have bikes with freewheels I'm happy with, I have my heavy load tourer on a hub. On freewheel I prefer 5-speed freewheels, 120mm axles. The way freewheels work the longer you go on the axle/sprocket count the weaker it gets.
That said, the 700c wheel/hub set in question is the only one I'll have to use here, and rebuilding the rear wheel for a free hub/cassette isn't an option.
#27
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Thread Starter
So the tire/fender gap question is solved with a wine cork.
Now I need to decided whether to:
A) Continue using the 7sp freewheel and use a shorter fender screw. The closeness of the freewheel to the chain stay seems like it may not be an issue.
B) Find a 6sp freewheel. This would be in spec measurement wise, if it matters, and give me the chance to get a less worn freewheel, though this one isn't. bad.
Now I need to decided whether to:
A) Continue using the 7sp freewheel and use a shorter fender screw. The closeness of the freewheel to the chain stay seems like it may not be an issue.
B) Find a 6sp freewheel. This would be in spec measurement wise, if it matters, and give me the chance to get a less worn freewheel, though this one isn't. bad.
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#29
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Yes! Another vote for the Spring Thing! Being able to remove the wheel without deflating the tire is a huge bonus.
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#30
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According to the '83 catalog, these came with an ultra six speed freewheel, which is the same width or just slightly wider than a five speed and narrower than a standard six or a seven a helicomatic six speed . As John said above, it wasn't designed for a seven speed, and the solution is a six speed with Shimano compatible cog spacing, and / or seven speed and respacing the axle and re-dishing if needed.
#32
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Let me toss another consideration while you research FWs: Your Trek is set up with 1/2 step + granny. If you've never learned how that works, you owe it to yourself to check it out. My 620 had it and it was really really neat with the original Helicomatic. It was almost as neat with 700c Shimano hubs and a FW I had on hand. I was about to go custom FW with IRD when I sold the TREK.
So....play with a gear calculator and the FWs you are considering, stay 6 speed, have a look at IRD (I think they are fine), or have Pastorbob build you one, have fun.
So....play with a gear calculator and the FWs you are considering, stay 6 speed, have a look at IRD (I think they are fine), or have Pastorbob build you one, have fun.
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I don't do: disks, tubeless, e-shifting, or bead head nymphs.
I don't do: disks, tubeless, e-shifting, or bead head nymphs.
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#33
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Let me toss another consideration while you research FWs: Your Trek is set up with 1/2 step + granny. If you've never learned how that works, you owe it to yourself to check it out. My 620 had it and it was really really neat with the original Helicomatic. It was almost as neat with 700c Shimano hubs and a FW I had on hand. I was about to go custom FW with IRD when I sold the TREK.
So....play with a gear calculator and the FWs you are considering, stay 6 speed, have a look at IRD (I think they are fine), or have Pastorbob build you one, have fun.
So....play with a gear calculator and the FWs you are considering, stay 6 speed, have a look at IRD (I think they are fine), or have Pastorbob build you one, have fun.
The pastorbobnlnh idea isn’t a bad one. He helped me out with a freewheel cleaning about 6 years ago and it was a great service.
#34
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Thread Starter
Update: Pulled the trigger on a nice looking Shimano 600 EX 13-24 (MF6208). We'll see how this goes.
#35
You would have gotten a giant improvement on your shifting if you would have gone with the hyperglide I mentioned, specially under load. It would have also been at a fraction of the cost.
#36
Senior Member
An 83" Trek 720 is one of the most perfectly designed bicycles ever made. Some of us have put many thousands of miles on ours, under a wide variety of conditions, over many years. It was designed as a 126mm 6-speed. Keep it that way. It's no surprise that the donor wheel with the 7-speed doesn't fit very well. It's not supposed to.
You're on the right path buying a replacement 6-speed, but as someone else pointed out, could you have found a HG version? Hyperglide really does shift smoother.
#37
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Thread Starter
#38
https://www.amazon.com/Shimano-TZ500.../dp/B073XV284Z
If you look at the teeth they are not evenly cut, they are designed so when you shift teeth on the next sprocket engage the chain before it leaves the previous one. This gives you oh so much better shifting specially under load, which considering yours is a touring bike I would think you will face that more often than not.
Long story short Hyperglide is the technology they incorporated into their then new hub system which years later they retrofitted into the freewheels they still make.
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#39
None whatsoever.
An 83" Trek 720 is one of the most perfectly designed bicycles ever made. Some of us have put many thousands of miles on ours, under a wide variety of conditions, over many years. It was designed as a 126mm 6-speed. Keep it that way. It's no surprise that the donor wheel with the 7-speed doesn't fit very well. It's not supposed to.
You're on the right path buying a replacement 6-speed, but as someone else pointed out, could you have found a HG version? Hyperglide really does shift smoother.
An 83" Trek 720 is one of the most perfectly designed bicycles ever made. Some of us have put many thousands of miles on ours, under a wide variety of conditions, over many years. It was designed as a 126mm 6-speed. Keep it that way. It's no surprise that the donor wheel with the 7-speed doesn't fit very well. It's not supposed to.
You're on the right path buying a replacement 6-speed, but as someone else pointed out, could you have found a HG version? Hyperglide really does shift smoother.
#40
Senior Member
Sometimes there's too much negativity with armchair bikey forum experts that for some the best they've physically done is used a slip joint plier on removing hex head bolts (as seen on Youtube... not joking).
Its just a bike hub, axle thingy apparatus. There's nothing complicated, just hollow threaded rods, spacer / washers and nuts. All readily available and cost pittance. Don't ever think it. Have 6 speed freewheels on 120mm spaced and worked perfect for years. Seven speed Shimano Mega-range freewheel on 125mm spaced used with a heavy duty rigged early Trek 520. Also, years of using what the experts dread 'Helicomatic' hubs. Bye.
Its just a bike hub, axle thingy apparatus. There's nothing complicated, just hollow threaded rods, spacer / washers and nuts. All readily available and cost pittance. Don't ever think it. Have 6 speed freewheels on 120mm spaced and worked perfect for years. Seven speed Shimano Mega-range freewheel on 125mm spaced used with a heavy duty rigged early Trek 520. Also, years of using what the experts dread 'Helicomatic' hubs. Bye.
#41
Senior Member
Thread Starter
None whatsoever.
An 83" Trek 720 is one of the most perfectly designed bicycles ever made. Some of us have put many thousands of miles on ours, under a wide variety of conditions, over many years. It was designed as a 126mm 6-speed. Keep it that way. It's no surprise that the donor wheel with the 7-speed doesn't fit very well. It's not supposed to.
You're on the right path buying a replacement 6-speed, but as someone else pointed out, could you have found a HG version? Hyperglide really does shift smoother.
An 83" Trek 720 is one of the most perfectly designed bicycles ever made. Some of us have put many thousands of miles on ours, under a wide variety of conditions, over many years. It was designed as a 126mm 6-speed. Keep it that way. It's no surprise that the donor wheel with the 7-speed doesn't fit very well. It's not supposed to.
You're on the right path buying a replacement 6-speed, but as someone else pointed out, could you have found a HG version? Hyperglide really does shift smoother.
Here's one:
https://www.amazon.com/Shimano-TZ500.../dp/B073XV284Z
If you look at the teeth they are not evenly cut, they are designed so when you shift teeth on the next sprocket engage the chain before it leaves the previous one. This gives you oh so much better shifting specially under load, which considering yours is a touring bike I would think you will face that more often than not.
Long story short Hyperglide is the technology they incorporated into their then new hub system which years later they retrofitted into the freewheels they still make.
https://www.amazon.com/Shimano-TZ500.../dp/B073XV284Z
If you look at the teeth they are not evenly cut, they are designed so when you shift teeth on the next sprocket engage the chain before it leaves the previous one. This gives you oh so much better shifting specially under load, which considering yours is a touring bike I would think you will face that more often than not.
Long story short Hyperglide is the technology they incorporated into their then new hub system which years later they retrofitted into the freewheels they still make.
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#43
If it makes you feel better my otherwise full campagnolo '69 Schwinn Paramount has a twist tooth 5 speed Shimano free wheel. They don't make a 5 speed hyperglide but the twist tooth shifts better than the straight cut original free wheel.
#44
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#45
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#46
Senior Member
Thread Starter
If bent, possible to be a factory oversight? I don’t see any sign of damage or stress.
The more I look at it I’m wondering if the dropout itself is titled in a bit?
#47
Senior Member
It would be a good idea to check your dropout alignment. Does the axle seem straight on the wheel that came with it when you turn it? I don't know if I'd try to straighten the fender braze on by itself but if the dropout is out of alignment that should be straightened to avoid axle or bearing damage. And that could be why the braze on appears to be bent in.
Google dropout alignment tool. Its an easy and quick job if you know someone who has the tool and knows how to use it. Very simple to do.
Google dropout alignment tool. Its an easy and quick job if you know someone who has the tool and knows how to use it. Very simple to do.
Last edited by Hobbiano; 09-05-23 at 02:30 PM.
#48
Getting back to the bolt. It needs to be replaced with a stainless bolt that is cut to the correct length, no threads sticking out. After cutting, file the end to a slight dome shape, sand and then polish to a mirror finish. The mirror finish won’t affect the performance of the bike in any way but you’ll be able to look down with disdain on all those cyclists out there with unpolished bolts.
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#49
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That Drive side dropout definitely looks bent, but at least it's a fairly painless fix.
Regarding the 7speed freewheel, I have that same Sachs paired with 7speed Shimano bar ends and it shifts REALLY well in index mode. Sure not quite as nice as Hyperglide, but totally acceptable.
Your rear spacing also looks like it's enough to clear the chain, especially after addressing the bent dropout and too long fender screw. If the cain isn't rubbing the dropout, I'd ride as is.
I've seen a lot of comments regarding the potential for bent axels and/or weeker wheels do to the extra dish and I'm not discrediting those claims, but I'd think there are extra factors to consider. Like rider weight, loaded vs unloaded, type of terrain, etc. I personally wouldn't ride my 7speed freewheel bikes cross country, but have no worries riding them around town.
Regarding the 7speed freewheel, I have that same Sachs paired with 7speed Shimano bar ends and it shifts REALLY well in index mode. Sure not quite as nice as Hyperglide, but totally acceptable.
Your rear spacing also looks like it's enough to clear the chain, especially after addressing the bent dropout and too long fender screw. If the cain isn't rubbing the dropout, I'd ride as is.
I've seen a lot of comments regarding the potential for bent axels and/or weeker wheels do to the extra dish and I'm not discrediting those claims, but I'd think there are extra factors to consider. Like rider weight, loaded vs unloaded, type of terrain, etc. I personally wouldn't ride my 7speed freewheel bikes cross country, but have no worries riding them around town.