amazinmets733 said:What is largest cassette I can fit? Is swapping RD for a MTB RD a possibility?
How is it looking re max tire clearance?
HMMmm ...
[INDENT]It look as though the rear derailleur hanger is slightly longer than on a typical Raod bike, so if you had a rear derailleur with a longer cage then an 11-34 would be easily accomodated ...
[INDENT]I recall (unverified) some people claiming to be able to us an 11-32 Cassete with a short cage rear derailleur ...
[INDENT]You will need to adjust the B-screw on the back of the derailleur by turning it all the way IN ....
[INDENT]This is best done with the derailleur unattached OTHERWISE you will be grinding the tip of the screw into the the back of the derialleur hanger (not a good thing to do ... particularly when it is steel against aluminum) ...
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Replacing the 11t upper jockey wheel with a 10t wheel will ensure that a larger Cassete will work ...
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You can definitely replace the Ultegra rear derailleur with almost any Shimano MTB rear derailleur ...
[INDENT]You should be able to use a Cassette with a 36t Cog if you use a Shimano MTB rear derailleur.
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Almost ANY Shimano MTB rear derailleur be used ...
[INDENT]Personally, I recommend a RAPID RISE XT (760) rear derailleur if you are going to continue to use the 105 shifters ...
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You will probably find that with a frame which has cantilever brake callipers that the limitation to the maximum tire size will occur inside the chainstays ...
[INDENT]A typical "Hybrid" can probably accommodate 700-48 tires ... maybe, 700-53 when fenders are NOT attached ... but, it will be the side-knobs on non-road tires which will probably be THE limiting factor.
[INDENT]I have a 90s vintage GIANT "sports touring" frame which can accomodate 700-53 (29er) tires in lieu of 700-42 tires + fenders ...[/INDENT]
A CX frame might be able to accomodate 700-42 ("Hybrid"😉 tires ...
[INDENT]Determining the maximum tire size will really is a trial-and-error process ...
622-17 and/or 622-22 rims acccomdate fatter tires better than the rims which the 622-15 rims which most Road bikes typically had-or-have.
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Possibly worth repeating ...
[INDENT]... (a suspensionless 29er) is really the type of bike which you would possibly end up with in a year-or-two based on the type of non-paved riding you indicated ...
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BTW. The FELT DD70 which you were looking at could accomodate MASSIVE 4" tires ... that type of "fat tire" bike is best suited for sand-and-snow but can accomodate ANY smaller sized tires if you have a second set of wheels for the bike's frame.
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