Is riding a bicycle on Shabbat permitted within an eiruv, being ridden only on pavement (so no unintended plowing), for transportation and not exercise, and with the understanding that repairs aren't possible (so you'd have to get off and walk it)?
As mentioned in my answer to the question "If no one else was available, could a mohel ride a bicycle on shabbos to perform a circumcision?":
According to the Ben Ish Chai, one can ride a bicycle on Shabbos inside an eiruv for leisure. Outside of an eruv, a mitzvah purpose might be needed, which includes attending shul to daven with a minyan, and certainly would include performing a bris. So, in summary, the Ben Ish Chai allows riding a bicycle, even outside of an eruv for a mitzvah purpose, and inside an eruv for even relaxation.
There are several issues that poskim have with a bicycle on Shabbat:
- Carrying/transferring in a public domain. (The bike is not considered part of the rider.)
- The bicycle may break, causing the rider to perhaps forget himself and fix it.
- Riding a bike is uvdin d'chol (weekday activity), and not appropriate on Shabbat.
- One might ride over soft soil, thereby transgressing the biblical prohibition against plowing. (Though the transgression in this case, I think would be Rabbinic.)
- A bicycle is muktza, as its primary use is for riding in public domains, which is generally hotza'ah (carrying), thus it is a kli shem'lachto l'issur (utensil that is designed primarily for a prohibited use).
- Even in a walled city, or one with an acceptable eruv, one may inadvertently ride outside of the eruv, or even outside of the t'chum shabbat.
For one or more of these reasons, many contemporary poskim prohibit riding a bicycle on Shabbat, though there have been those that have permitted it. As Joshua Lee linked in the comments, see here for a short discussion.
You implied in your question that perhaps riding a bike would be permitted with the understanding of the reason behind it being potentially prohibited, such as with the understanding that one may not ride over soft soil, or with the understanding that repairs may not be done. In general, the knowledge behind the reasoning of a rabbinic prohibition does not entitle one to transgress it. For example, the Sages felt it was necessary to forbid dancing on Shabbat, lest one come to bring musical accompaniment and further come to fix the instrument(s) if they break. This holds even if one understands that it is forbidden to fix instruments on Shabbat. We are still worried he may come to transgress a biblical prohibition.
Most people do not consider it proper on shabbat. Perhaps it has to do with the fear that you may come to fix it, but no actual gezerah was made forbidding it. It may also have to do with "uvda d'chol", a somewhat vague prohibition on doing weekday activity. Though there are some who allow it if you're in a place that does not have a minhag against it.
Joshua Lee posted this link in the comments that expands on this answer: http://www.dailyhalacha.com/Display.asp?PageIndex=48&ClipID=310 .
The Kaf Hachaim 404:8 argues with the Ben Ish Chai's ruling cited by Curiouser and forbids it.
It is assur for a few reasons
For one as you mentioned because of uvdin dechol, is not subjective. Rather it's defined as something that is primarily a non Shabbos activity. So just because you have no time to do it during the week doesn't remove the technical defintion or classification of the act of biking.
Secondly it's forbidden to ride it in a place where there is no eruv.
Furthermore it is forbidden because it's common to fix the chain or the spikes if it breaks. So it's forbidden for that fear. However, there are poskim (מראה הבזק) that would allow to use a bike if there is absolutely no concern of fixing it. However this opinion does not account for the uvdin dechol issue, as well as it disagrees with the most major halachic authorities.
This is all the more so an issue, as in the OP’s question, the riding for transportation and NOT for exercise, as for transportation is exactly the reason why it is Uvdin Dechol (see Rav Ovadia below)
See Rav Ovadia in Yalkut Yosef as well:
יש להורות למעשה שלא לרכוב על אופניים [המיועדים לאנשים גדולים] בשבת. ואין לפרוץ גזר בזה. [ילקוט יוסף שבת כרך ה עמוד נו]. ונכון מאד להחמיר שלא לנסוע בשבת על אופניים, אפילו כשרוצה ללכת לדבר מצוה, וכמו שהסכימו כן הרבה אחרונים משום עובדין דחול. ובאיסור שבת החמורה ראוי לחוש לדבריהם להחמיר. [יביע אומר ח''י חאו''ח סימן נד אות יב, ושם בהערות על רב פעלים ח''א בתחלה]. אבל אופניים קטנות תלת אופן [שלש גלגלים] המיועדות למשחק הילדים, מותר להניח לילדים שישחקו בהם בשבת, באופן שאין שם בטריה ולא נדלקת מנורה. [ילקו''י דיני חינוך קטן עמוד רטז]
See here as well with a bit more clarification into the opinion of Rav Ovadia:
Maran Harav Ovadia Yosef Shlit”a (in his Chazon Ovadia-Shabbat Part 4 page 43, as well as in his Responsa Yabia Omer Volume 10 in his comments on the Responsa Rav Pe’alim) agrees that riding a bicycle on Shabbat is prohibited based on what the Gemara in Masechet Shabbat (113a) writes, “’If you shall turn away your foot because of the Shabbat-by not making your ways,’ your mode of walking on Shabbat should not be like your mode of walking during the weekdays.” The Poskim derive from this Gemara that one may not run on Shabbat, as we shall discuss in the following Halacha. Thus, since bicycle-riding is meant for traveling a long distance which is not the usual way of walking on Shabbat, it is forbidden to ride bicycles on Shabbat. He proceeds to bring many sources to defend his opinion, one of which is based on the Gemara in Masechet Beitzah (25b) which states that one may not go out in a chair on Shabbat. This refers to the custom of an important figure sitting in a chair and being carried around by people to his destination of choice (as is common in some lands in the Far East even today). Our Sages prohibited this practice on Shabbat, for this is not respectful to the Shabbat as this is considered a weekday mode of travel. Maran Shlit”a brings other reasons to be stringent as well. Thus, halachically speaking, one should not be lenient to ride a bicycle on Shabbat; even if one is doing so for the purpose of performing a Mitzvah, one should still act stringently regarding this matter. We shall, G-d-willing, discuss the laws regarding bicycle-riding for children in the Halacha that will be published on Thursday.