Component Substitution of Deraileur on Rad Mini 4

[TNOutback]

I received my Rad Mini 4 yesterday, and noticed the derailleur on the bike is a "Mezzu MicroShift" and not the Shimano Altus that the bike is advertised to have.  Anyone else experiencing substituted components?  I'm sure it is a sourcing issue, but I'm a bit bummed.  It's a pretty clunky and loud derailleur.  My wife heard me shifting gears and asked, "is something wrong with the bike?".   

[RadJohn]

Rad, like most companies, probably has one of those "Specifications subject to change without notice" clauses tucked away somewhere so I don't know if complaining to them will accomplish anything other than letting them know how much people like us hate them invoking it to weasel out providing us with what we paid for and thought we would be getting.

Mezzu MicroShift components have been around and available on Amazon and eBay for a while as cheaper alternatives to the more familiar name brands and have received mixed reviews, from no problems to crap, so it's difficult to say whether you should give it a try or just replace it with an Altus (I've never used or had a bike that came with them).

My Altus equipped (June) 2020 RadMini 4 has never been particularly quite in the shifting department, but has improved a bit with time. I always attributed that to the DNP Epoch Freewheel which is kind of notorious for noisy, but fairly reliable shifting. I borrowed a higher end Shimano Deore off one of my other bikes and tried it in place the OEM Altus for a while and although it worked well, I didn't see any obvious benefit/improvement so I took it off and went back to the Altus.

The only obvious substitution on my bike as delivered was a KungFu or something I've never heard of brand chain in place of the advertised well know and highly regarded as bulletproof KMC Z7. I have spare Z7s but didn't get around to changing it right away and now, 3800+ miles later, the KungFu is still cranking out the miles, having been inspected, cleaned and lubed about 10 times. Even so, I'm not totally on board with accepting the replacement of every familiar to me component with something that will force me to abandon my preconceptions/prejudices and broaden my horizons, at least not yet, and maybe never. 

[joelee]

Our Rad Mini ST2 is a week old, and has the same Microshift Mezzo deraileur. The bike will not stay in 6th gear without trying to shift. All other gears are OK, and I've made the adjustments to deraileur per Rad video online. On close inspection it looks like one of the teeth on the guide pulley is bent. Also, inspection of the cassette, (or cogset) shows that several of the teeth are slightly bent out of place. When I unpackaged the bike the chain was not on the front sprocket, but resting on the inside of it, by the frame. Not sure if this little bit of torque on the cassette could have bent the teeth, but I guess it is possible. In either case, I will be contacting RPB today to try and get resolution, and express my disappointment with their choice of substitution parts. I've used Shimano gearing on my bikes for over 50 years, and have never seen anything like this. Will post when I get a resolution.

[TNOutback]

Joelee the chain was off the front chain ring when I unpacked mine as well, and I believe it is intended that way to keep tension off the deraileur.  My bike likes to skip 6 gear; very difficult to get it to settle into 6th.  Otherwise it is loud and clunky, but working.

[pjmeyer4]

I am having the same issue.  Just received my Mini this week.  Substitute parts.  Won't shift or stay in 6th gear.  Please post a resolution when possible.  Thanks

[RadJohn]

Strange, even though this thread wasn't originally posted to the Mini specific subsection of this forum, it appears that all reports of similar problems so so far relate to Minis. which makes one wonder if these problems are related to a recent specific build lot or lots...

Several possible causes for something like this come to mind:

Since virtually all modern bikes use "indexed" shifting systems (like Shimanos SiS), and the "detents" that control where the rear derailleur stops for each gear are located in the shift selector mechanism on the handler (NOT in the rear derailleur itself), could someone report whether Rad has also changed the selector to a Mezzu supplied unit as well? The ones Rad has used with Shimano Altus RD equipped bikes in the (recent) past have been silver colored  Shimano SLTX50 Tourney (right) Thumb Shifters, clearly marked "SHIMANO 7 SPEED" and "SiS INDEX". It generally doesn't hurt to mix shifter component manufacturers (shifter, cables, derailleur), as long as each component (particularly the handlebar mounted shift selection mechanism) adheres to industry standard pull distance increment/detent spacing specifications. Shimano SLTX50 Tourney Right Thumb Shifters are easily obtainable on the internets (and sometimes available from Rad), and are easily replaceable.

Another possibility is that Rad got hold of a batch of DNP Epoch 11-34 Freewheels with an incorrect thickness spacer between two of the cogs, probably either the 5-6 or 6-7 spacer. Freewheels like Rad uses (unlike Cassettes)  can't be disassembled to replace individual components so they have to be swapped out as a unit. DNP Epoch 11-34 Freewheels are usually available on the internets (at least they were in pre-COVID bicycle component shortage days), but require special tools to install.

Again related to the DNP Epoch 11-34 Freewheel, IF something were wrong with  the tooth profile on the 6th speed cog or its shifting ramps, problems such as those reported could occur. This could be due to a manufacturing defect such as a worn out stamping die or a bunch of other things.  It's also possible that either the adjacent 5th or 7th speed cog teeth/shiifting ramps could be misshapen, but if that were true, one would expect the problem to only be present when shifting in one direction, UP, or DOWN, but not both.

The final thing that comes to mind involves some miscalculation involving the geometry of the four-bar linkage used in the Mezzu rear derailleur, and although that one gets complicated, Shimano Altus replacements like those used in earlier Rads are (or were) obtainable on the internets and from Rad.

Then there's the possibility that the problem might become less severe or even go away as parts wear in (most likely if slightly misshapen cog teeth are what's causing this problem), only time will tell, and it might help to understand what's going on here if people reported their bike model and total mileage when posting about the problem.

[TNOutback]

could someone report whether Rad has also changed the selector to a Mezzu supplied unit as well?.

The shift selector on the handlebar of my Mini is still the Shimano shifter, so indeed we have mixed components.

[SergeL]

Our Rad Mini ST2 is a week old, and has the same Microshift Mezzo deraileur. The bike will not stay in 6th gear without trying to shift. All other gears are OK, and I've made the adjustments to deraileur per Rad video online. On close inspection it looks like one of the teeth on the guide pulley is bent. Also, inspection of the cassette, (or cogset) shows that several of the teeth are slightly bent out of place. When I unpackaged the bike the chain was not on the front sprocket, but resting on the inside of it, by the frame. Not sure if this little bit of torque on the cassette could have bent the teeth, but I guess it is possible. In either case, I will be contacting RPB today to try and get resolution, and express my disappointment with their choice of substitution parts. I've used Shimano gearing on my bikes for over 50 years, and have never seen anything like this. Will post when I get a resolution.

Same thing here, re substitution derailleur and shifty 6th gear on a RadMini ST2 received this past mid-August. What was Rad's reply to your concern? Reply I got was not really helpful, roughly along the lines of « easy fix, your derailleur needs adjusting, please check our online guide at https etc. I figured a way to work around the issue by fiddling with the barrel adjuster (7 clicks counter-clockwise as seen from behind, so far. At about four clicks, the shiftiness went from 6th to 2nd gear, now seems tamed, at least for the time being). Oh, and the quite experienced bike mechanic who delivered the bike and performed the final adustments and fine-tuning had had quite a time getting it almost there.

[SergeL]

I have the Microshift Mezzo as well on my (2021) RadMini ST2, with Shimano shifter. Been doing some digging, and looks like Microshift is based in Taiwan, with an office in Bloomington. They list several OE partners, such as Giant, Cannondale, Cube, etc.

Interestingly, going through Microshift's 2021 and 2020 catalogues, I see the Mezzo is listed as an 8-9 speed rear derailleur ("Mezzo Rear Derailleur 8/9 Speed Long Cage - RD-M36L" as an example, since I am not sure which one we have, short or long). Here is a link to the Mezzo group page https://www.microshift.com/products/groups/mezzo/

Could this use of an 8-9 speed-intended derailleur with a 7-speed indexed shifter explain why some of us have those "jumpy gears"? Should I try to get a Shimano derailleur on my own and hope it fixes the issue? Long or short cage?

Thanks!